Sorry to be the dampner but problems :-
1) Mythic pet from normal bracken? Whatever be the chances thats overkill, imagine a lvl 5 looting it.
2) Bro any arena-player knows that mythic recipe loot is the worst AL chance loot. I would rather buy a mythic gear twice then hope for a loot with recipe.

For the AP , you can't keep it to any map below elite nordr, then the mythic AP is a waste.
Maybe 20 run each of all the elite bosses till shuyal will give you the tokens/frags you need to craft this