Since this is a completionist run, add this:
- Have all the Mega Stones by the end of the aftergame
- Have 1 of every item used in competitive battling
Also, since you're going to catch every single pokemon catchable, an interesting thing you could do, is always train a group of 5 pokes before the next gym (If you have the spare time for it, of course).That way, you'll catch things, evolve them, and make them useful :]
Well, good luck doing what i do normally xD