I have gone back and thought and agreed with my original conclusion.  The most important thing about Mac on Demonreach is the way his actions are different than those in his pub when Sharkface the Outsider shows up.

In his pub, he actively gets weapons and tells Harry to kill the Outsiders.  He knows about Outsiders and wants them dead.  He does not act passively.  In this case, he defends his turf against an Outsider attack.  Almost like he was a previous Gatekeeper or Defender of the Outer Gates.  Once the threat is gone, Mac returns to past behavior.

On Demonreach, Mac is back to standing around waiting for things to happen.  He does not join the fight nor does he provide any commentary that would be helpful.  He simply does not offend. My assumption on his shooting is different.  Nemesis gets a nice clean shot at him.  Maeve thinks she is going to win, so no need to kill him quickly.  However, she does put him out of commission.  I think this comes from Nemesis in knowing who/what Mac is from an Outsider perspective (my base assumption is that Nemesis and the Outsiders act in concert - though we have no absolute proof of that).

So, you are saying that Lea AT ALL TIMES was watching Harry.  She was NEVER EVER doing anything else. 

That's not really an inconsistency.  Faeries are pretty fast in general, and Lea had Maggie Sr.'s NN notes.  Lea has the stamina to not worry much about whatever NN environment she's going into next, so no slowing down there.  Not to mention whatever option Odin came up with post-Chichen Itza is probably available to her in a pinch.  Shadowing Harry shouldn't be all that difficult for Lea.  Basically, "close" is relative to the ability to travel quickly.

1.  Showing up in 5 minutes no matter WHERE he was in the NN takes more than knowing the ways.  (GP)

2.  She had to bargain with Odin to get the insta-gate (Changes).

3.  All the beings chasing Harry from AT could not catch Harry and Team (PG).

So we have to reconcile all the places that Harry went in GP and say they are very near her garden in the NN - which makes no sense as Agatha Hagglethorn lived in her own pocket dimension.

If you're interested in the lore here, I think reading Into the Jungle would be relevant to your interest

I don't read any of it.  I listen to audiobooks, which makes almost no sense with comics.  My take on the way things go in terms of relevance:

1 - WoJ: However, they tend to be quite fae-like and often not specific.
2 - Novels: Later is better than earlier.  There are some number of retcons and changes to things.
3 - Short Stories:  Most of them seem to be more "fun" than part of the lore.  Mistakes can be made.
4 - Comics: See 3.
5 - TV Show:  Well it has to go somewhere.
6 - Fan Fiction/Speculation:  What I am trying to say with all the work that we do, it can all be wiped out by one piece of verbage from JB.  There are quite a large number of theories about different things.  Many of them directly contradict one another AND have ways of tying to the lore.  There are things that will likely never be reconciled.  Will we ever find out who fixed LC?   Who ran Harry off the road?  What was the grand plot behind the attack on AT?  I have theories on all of them, but none of them can be proven.  For example, we recently discussed Maggie spending her summer vacation on DR (which I still don't know where Quantus got that nugget from).  EG and I were discussing why Maggie might not be affected by the bad vibes.  I see where that makes sense from an author's standpoint, but struggle to find a way for it to come out of what has been written about DR.

Kumori resurrected a Human and broke one of the 7 laws.  It was black magic.

Which mantles were created by Black Magic Ascension?  For all we know the Faerie Queen Mantles were created originally by TWG.  We actually have no information about their origin.  All we have is an explanation that a Darkhallow, done correctly, would create something with powers of a "God" (does that mean Mab like, Molly like, MW like, Hades like - we have no idea). If that being was subsequently killed on Halloween, we have no idea if that became a "mantle" and passed on.

Wow - okay well there you go...

We have no idea so we invented some mechanisms.  Or how about idea 4.  Siriothrax is dead, never to return since not all beings have a cosmic purpose.

If Jim didn't actually mean mantle when he said mantle, it's not exactly hard to come up with a different phrasing for Bob to use in that sentence.  I just think that the text and WoJ point more toward all true immortals having mantles. 

No I think it was a way for Bob to explain how the exchange power.  The conversation was heavily Fae oriented at that point and the Queens in specific, so I think Bob just carried along in the conversation.

So again, every Naagloshii is a mantle as well?  Outsiders as well or just Walkers?

To me, there are positions within the Universe that were set up that need to exist.  Then there are other structures that could exist.  Those that need to exist at all times are mantles (which is why Warden of DR can't possibly be a mantle).  Mantleship means that there is a position to be filled.  Not all immortals fill a position.  For example, non-Archangels.  Naagloshii.  Dragons.  Lea.  They are just beings.  Are some/all the gods mantles? Maybe.  But the implication in Norse Mythology is that if Thor took over for Odin, he would still be Thor and would not eventually be Odin.  There are some examples of this in Greek Mythology as well.

That makes an assumption that all immortals that are killed on Halloween will actually have their "mantles" transferred.  We have exactly no evidence of that.  What Bob actually says is that the immortals take small amounts of power from one another (i.e. They Trick or Treat).