I'll probably need more than a list of names if I'm going to be invoking pacts with them...
I'll be in the same boat as you. As it happens, Magnus was going that same route (though from the talisman side of things).
I guess we just have to make a few up. I really haven't given it a proper amount of consideration. Do you have any thoughts on what might be workable?
The might limit is defined by the rituals, so create magical NPC companions and assume any Daimon that can still be summoned reasonably is an autumn character for experience (plus any bought with qualities), disallowing decreased and increased might qualities/inferiorities?
On the other hand Dietrich von Bern has what amounts to a ritual ability tat is paid for with regular might expenditure...
That seems a reasonable starting point. Let's go with that and see if it works well.
In considering my first daimon I have found a single issue- ritual powers. Even if an aspect gave up magic might (or confidence) I do not see where this would impact the daimon, unless it simply has to re-earn the confidence somewhere off-screen, and as mentioned before there is an example of a daimon using a ritual effect which only costs temporary might points. I'm also wanting to summon a daimon which can empower a place with a might:1 aura where no aura previously existed...obviously no guideline exists for the magnitude of such an effect...
It seems to me that a simple binding would be unlikely to get a daimon to permanently expend Might or Confidence. Yes, both could technically be gained back again. But that takes effort. They don't just regenerate with time.
Getting a daimon to spend temporary Might points is relatively straightforward. They'll come back in time without any effort on the part of the daimon.
If there is no guideline provided, is that something that a daimon can do?
My point is that it seems a daimon may be able to effect ritual powers without expending might or confidence, as per the Dietrich von Bern writeup in mysteries. Also it specifies that Gydryty-kom the Giant can cast ritual spells as formulaic spells under what would otherwise seem to be a focus power.
As to what a daimon can do, the implication is that the limits ae up to the storyguide, or the troupe, depending on how the game is being governed. The question of how the effect is achieved may not follow standard rules either apparently... as things currently stand an aura can be improved (Meliai has spells for that) but there is no known way to create an anchor... which is not the same as to say it can't be done, just not with Hermetic magic at this point. It does state in ROP:M that any pace inhabited by a magic being for more than a year will have a tether (aura) equal to it's might/10, and the site of the death or burial of a magical being, or where it spent the last half of its life will develop a magical aura of might/20- neither of which really answers the question unless the daimon creates and binds a creature of might 10 to the location which does manifest an aura (which is an elemental does that Ook may be able to do that...)
This is a high-level game, and so I should allow higher level effects into it. (If not here, then where?) My only concern is that I don't want to have anything unbalance the game. Further, I don't want to say yes, only to then have to go back and later say no should it become evident that a ruling was, in retrospect, unwise. I understand that such action can frustrate players who put effort into using the ruling in question only to have the rug pulled out from under them. I don't want to be a source of such frustration, so I've tried to be conservative.
Now, that having been said, if people are willing to try certain rulings with the understanding that if they later prove unworkable or overpowering in the eyes of the troupe that they may be withdrawn, I'm good with that. But if I'm stuck with a yes forever, then I'm going to be very, very careful about what I say yes to that's on the edge of the rules. I'm very cognizant that there are many working parts in ArM5, and that its easy for the law of unintended consequences to take over.
Thoughts?
Correct.
I've never heard of Magic Theory being taught by training. It seems like an odd idea. Training is described as the trainer showing the trainee what to do, and notes that it can even be done without a common language. That seems totally at odds with how MT should be learned.
I'd say MT can be trained just like any other ability. Books, direct training, group training all seem valid to me.
However I don't think a season doing something like lab improvement can also be proper training too. The needs of the student are the focus in training, not in other lab activity.
I'd also vote on allowing training. Just remember, while the trainer can work, the trainee does nothing save learning.
Huh? The trainee does nothing except gain experience. Are you saying the trainer can't improve a lab and train someone?
Sorry, I was confusing teaching and training. Makes sense then.
Would a companion priest be against the wishes of the group?
I'm struggling to come up with ideas at present (I think because there is so much other stuff to write/do), but we've not a lot of religious representation as yet.
A "Scottish style" priest as written about in Lion of the North, tolerant but faithful.
Good or silly?
That doesn't seem an unreasonable concept to me. In fact, as you note, you'll be dealing with the Church whether you like it or not. So having a friendly priest around could be an advantage.
Would this be of the Catholic tradition or the Irish Monastic?
Haestus has some extreme religious views; since Atlantis is unspoiled territory and run by magi for magi, he is of the opinion that organized religion should be banned. Religion and observance? yes, maybe, can't really do without I suppose. Churches that can create a dominion aura? Heck no!
So it would be awesome to have a pious and devout companion!
I'm sure the Church will be totally respectful of that attitude. 
Oh, and Meliai is pagan. Like, seriously pagan...so your churchman might come across an avatar of Selene for example... especially after... well that's some long term planning...
I can hardly wait until the first Crusade against Atlantis. 