The server does the comps based on avq, so yes, you'll be in a league with similar avqs, still in higher levels, where there are just 2, 3,4 leagues in a single level, you'll not be placed in such a low avq group because there aren't low avq teams there.

Its exactly the same, if you promote or not, the next season, with same level or +1, the draw will work in same way, taking into account your best 14 avq.