I don't see why not, but you'll probably get pushback from people who don't like seeing magicy types stepping on areas where pure mortals are usually superior. 

Hmmm… Maybe a specially shaped shield attuned solely to heat in the preferred shape of the blade?  That way you won’t set yourself on fire unless you botch your attack roll.   It’d probably be a lot of work, but the nerd in me is trying to figure out exactly how much effort would be too much to have a lightsaber and “lots of months” seems a small price to pay. 

To get back to the topic at hand, are you (OP) worried about the actual game mechanics of your devices or just brainstorming for backstory?

If you’re looking for mechanics I’d suggest a Lore stunt that allows the character to steal the Equipment trapping of Wealth for mundane arcane gadgets, provided the magical version apes the mundane version precisely (ie. if you want to drive with Discipline you’d need to buy it with refinements.) 

I concur.  If you’re thinking “but that means it’s practically impossible for the WCV to actually lose their shit” I also agree.  My group has been playing for over a year now and I’ve yet to see my WCV player actually be inconvenienced by it. 

Bear in mind that just because it says "traitor" in your notes doesn't mean he has to be.  It's not cheating if the GM is doing it.

Whenever it makes sense.  When we started playing I had to occasionally force them to splitting up to do anything of substance, especially meeting contacts.  They had a more traditional gaming background, and it took a while for them to believe me when I said I wouldn’t use the fact that they were alone to hose them.  For all that their backgrounds are usually those of a sociopathic loner with a dark past PCs sure do hate doing anything without their three closest friends in tow.

That said I try to limit alone time so no one gets bored at the table.  Fortunately my players are mature and don’t get bored and restive the instant it isn’t about them, but one can only spend so long watching other people have fun (especially when it’s fun you have to act like you didn’t see) before the smart phone beckons.

I've found that removing the control bonus to attack rolls was all that was needed to balance Wizards.  Evocation's potential damage is balanced by the stress and refresh costs. 

There are really two questions that people seem to be answering, 1) do BBEGs have cemented stats at all, and do you as GM stat your BBEGs ahead of time.  To answer question two, I don't stat out all my NPCs ahead of time, but once I do stat them they stay statted absent some legitimate reason for the stats to change (accept a pact for more power or suchlike.) 

As for the first question, I understand that other GMs may have different opinions on the matter, but I think that anyone, or anything, the PCs come into conflict with should either have stats or be so insanely better than them that the stats become meaningless.  Stories include setbacks as well as victories, and I don't think it's the GM's place to determine which the players will experience ahead of time, and fudging NPC stats to determine which side comes out on top of a given conflict does weaken the game. 

One of the most challenging aspects of running Fate for me has been creating victory conditions for my NPCs other than "I kill all the PCs," so if a conflict goes south on my players I don't have to choose between handing them a hollow victory they didn't earn or allowing the players to be wiped out.  Fortunately concessions make that a lot easier.