While 'murder hobo' is the default PC, a workable character in Dresdenverse who relies on wealth and contacts to solve their problems. A starting PC can blow through the roof of the Buying Things chart on p322; it stops with a Legendary Resources roll (+8), granting a large corporation or a small personal island; but with Resources 4, High Concept of Rich Investor, Trouble of an Obligation to build up the family wealth, plus 5 money related Aspects, the PC is looking at +18 before rolling the dice!

The PC is easily able to create a Major Milestone every session, simply buying problem locations out from under the bad guys and gentrifying them. (Of course, the bulk of the session will then be surviving the wrath of the critters you've chased out).  While the rules suggest downgrading the rewards for doing so in a single session, that is punishing skilled play, a massive no-no: far better for the GM to say that the PC's reward is a free Resources Stunt of their choice. That is realistic, fair, balanced, and has the ethical dilemma of whether to buy Filthy Lucre – a temptation that will grow stronger each time, as the pool of available Stunts shrinks.

Anyway, the PC has far more successes than they need. Some of those successes may be needed for overcoming seller resistance of course; but if a location has been ruined by monsters, they'll probably be eager to sell. The simplest thing to do with those extra successes is to buy quality, giving the corporation extra stress boxes: the example above could have a quality of +10, giving it an additional +5 stress boxes (p320+p130). That's fairly inefficient though; the corporation is getting one stress box for every two successes – they are less well defended than an ordinary quality organisation of legendary size.

A better option is to have subsidiary organisations that provide the organisation with 'Armor'. An established contract could be bought for one success, providing Armor:1 in the desired realm; or the subsidiary could be bought outright, and provide temporary Aspects when attacking/defending in Corporate warfare.
My suggested subsidiaries are:

Physical: Security, Maintenance, Insurance, Cleaning

Mental: Legal, Accounting,  Political, Personnel

Social Armor: Public Relations, Real Estate, Murals(the giant wall ads that companies have painted that get around restrictions on billboards), Plant hire.

This has the advantage from a GM perspective that you can assign these to a company to make it harder to gain control of – but since they come with the company, increase the reward for succeeding.

Police contacts, I would simply halve the benefit of using Filthy Lucre.

Some supernatural defences can be put in quite easily by having access to an employment agency! How many mortals would have access to Bless This House – one in a hundred? Unlikely, unless a particularly devout community. One in a thousand?  Possible. One in ten thousand? Definitely. Your city will have hundreds of thousands of people in employment, providing a pool of defenders, who are easily identified by having a supernatural entering and leaving a building while job applicants are arriving.
Similarly, 'allowing' workers to hold their weddings etc for free at the business allows the possibility of rending the place to toxic to Raith Vampires. Those turgid inspirational posters are probably an unsuccessful attempt to protect the place from Skavis Vampires.

A couple of examples:
The PC is going to buy a housing estate being preyed on by ghouls. They tag the Aspect of 'invested by Ghouls' to allow an easy sale, and focus on physical security; the tenants are moved out into temporary accommodation elsewhere (easily justified by claiming the building isn't safe – which it isn't) and a week later when the ghouls have had to go hunting elsewhere, the building is repaired, repainted, and fortified, with alarms and security. Supernaturally, a 'leaking' pipes are slowly dripping holy water into the entrances from undercity.  That's a success for handling the move, plus 5 for redoing the building, plus needing a church contact to provide the holy water tag. The PC can do this easily, allowing them to keep a few Fate points for when the Ghouls attempt to follow their prey to the temporary accommodation, and/or attack the repair crews.

The PC wants to acquire a very fashionable White Court Nightclub. Although 'only' requiring a Fantastic (+) result, the Quality is sufficient to give it 3 additional stress boxes, and is Armored to the max; further, they don't want to sell. The PCs start their campaign by getting some noise violations thrown at the place: but Social Armor will protect here. They investigate buying the entire building and simply ejecting/replacing the night club (a common real world tactic, lets the buyer acquire the good will of the site for free) but the White Court either has the building or is relying on the Armor: Real Estate; either way blocked. The PCs investigate the possibilities of violence (because they are the PCs) but are then surprised to learn that the White Court is now offering the place for sale. An Investigation roll is made, and the PCs learn that the White Court is buying another location nearby and planning to move: the existing night club will be 'sold' but the bulk of the clientele will be moving with them, so they are selling a turkey. The PCs chose not to buy, and instead begin working on the new site: but a newbie Black Court Vampire buys the old site off the White Court! The old night club will fail, but the PCs have to decide whether they want to tolerate the deaths that will take place before that happens – do they focus on eliminating the Black Court Vampire, or continue the war against the White Court (who are more vulnerable due to the move).

Real world, the tale of St Patrick banishing snakes from Ireland is a reference to the Draconis, the war banner/streamers, and refers to him bringing peace to the island. But in Dresdenverse, you could well have a race of snake-demons who've been banished from their home and want to come back.

The Giant's Causeway might allow travel to Scotland; or the group might be asked to repair it - allowing invasions of giants.

Ireland is surprisingly young; when the ice retreated, Ireland was just a flat piece of rock. Winter might resent this johnnie-come-lately nation.

Ireland is surrounded by mythical nations; Hy Brasil to the west, Ys and Lyonesse to the south, Thule to the north, Cantre'r Gwaelod (and Sodor!) to the east. For that matter, the Isle of Man is important in the Arthurian myths as the home of the Fisher King.

In Britain, Arthur pulls the sword out of the stone; in Ireland, Cúchulainn drove his sword *into* the kingstone, the Lia Fáil. The Scots insist that their king stone came from ireland, the Irish that their came from Scotland - that has potential for lunacy. Suppose the stone sang again when a (n)pc approached it? How would the PCs reacted to knowing who the rightful king of Ireland was?

trust you've seen xkcd's take on the pot of gold at the end of the rainbow? https://m.xkcd.com/1944/
Gold isn't created by normal fusion in the Sun though, it needs a supernova.

In Dresden verse though, you'd follow a rainbow through the NeverNever, to the pot of gold. Unless you just want a pot of ectoplasm when you get home, you'd need to open a gate into the Sun - which is at least a quick and painless way to die. However, you could then (in the middle of the blasted wasteland in the Never Never) have cooling gold, which could be collected by someone else.

So a sneaky, evil Leprechaun could spread rumours of having a pot of gold, allow himself to be 'captured' by a Wizard with no Scholarship, and lead them to the appropriate point in the Never Never. One instantly fried Wizard later - massive riches! The joy of it is, they aren't lying - they *are* taking you to their pot of gold.

Leprechaun should have Mythic Immunity to Sunlight, and possibly have received a death curse or 3. 

If wizards are mechanically overpowered, that's a manageable issue. If wizards are the True Protagonists, that's a catastrophic issue.

[nods]
And the thing is - they clearly are not.
The gimmick of the game is that is written by a werewolf, with input from a pair of vanilla mortals who moonlight as Knights, a talking skull and, yes, a wizard...who repeatedly goes on about not underestimating mortals/lesser talents and so forth.
The books are really the story of "who gets to slap Dresden around this week", or possibly "humans Mouse has owned".

this conversation would be easier if there were more +1 IoP in the books to use for comparison...actually, are there any?

In combat, wizards tend to be fragile unless they're specialised in crafting.

Interesting exception. Why are crafters tougher?

A rules clarification that I don't think anyone will need, but has been bugging me:

If the Clever Man casts the 'document forging' Stunt as a Spell, this will not allow him to create permanent documents, it will merely allow him to pretend to have those documents for the duration of the spell. (Don't under-estimate the effect of confidence here - during security tests I'm aware of at [classified], one of the testers got into a high security building by flashing an orange instead of a security pass. Security there was promptly tightened, but still)...