About Takhysis being kept in he Abyss, you could argue that other godlike powers bestowed by Huma prevented her powers of being everywhere from happening. You could say being everywhere doesn't come in free for the gods but requires an effort of them and that the other gods can try to prevent it. Although it is too philosophical. There are a lot of paradoxes pointed at godlike abilities. Such if god is all powerful can he create a rock that he cannot lift? And so on. Also, gods can manipulate and travel time and this comes also with bunch of paradoxes.
In short I would say that if nothing is working against the god there is no reason he or one of his avatars would be at the same time at different places, but if other equally powerful forces are aiming against him (/her/it) then it might reduce his powers and it might be a problem for him to manifest his powers.
In any case I think that in places that are sacred to the god, the balance is tilted toward the god and against other gods so even if he is under "attack" he would still be stronger there, and if a Priest have such a special place which is important to him and his god, (which is a likely place to find folllowers, make rituals and later build a church), then there the chance of meeting the god is higher. It might not be a true avatar but some kind of a true miracle or reflection or whatever. In the old testimony AFAIK no encounter with god was in true form. In fact it is said men can not capture the true form of god (maybe women can
). Instead he was seen by his miracles or in one case as a bush on fire... In the new testimony there is of course the son and the dove which could be compared to avatars, but I'd be careful there since I'm not religious and don't want to hurt anyone by my ignorance.
