Yveltal, Fighting Fury Belt, Hex Maniac, and Order of Operations Between Turns

[bullados]

This is an extension of this topic.

Player A has a Pokémon with 70hp left. Fighting Fury Belt is attached, and has played a Hex Maniac during his or her turn.
Player B attacks using Shaymin EX’s Sky Return, does 30 damage and returns to the hand.
Player A’s Pokemon is still alive due to Fighting Fury Belt (40 HP left)
Player B promotes Yveltal (BKT) with the Fright Night Ability which shuts off tools
Player A’s Pokemon still has 40 HP remaining.
Player A's turn ends, removing the effect of Hex Maniac and reinstating the effect of Yveltal.
Player A's Pokemon is Knocked Out.

Question: When is Player A's Pokemon removed from play and a new Pokemon promoted? During the Between Turns phase? Before? After?

I ask because of Page 15 of the Rulebook (containing a piece of information about order of operations that I didn't know about) checking for KOs during the between turns phase.

I think that the KO check would happen at the end of the in between turns phase, due to the order of operations outlined in that rulebook, but I just wanted to make sure.

Thanks for the help!