Rescue Energy vs. Remove Lost

[waterfox17]

If my pokemon has a Rescue Energy attached, and my opponent uses Dialga Lv. X's "Remove Lost" and knocks out my Pokemon with the 80 damage, does the knockout happen first to return my pokemon to my hand, or does he flip a coin to remove my rescue energy as a condition of the attack, preventing me from getting back my pokemon?


In addition, does he choose the energy to be discarded, or do I choose?

 

[PokePop]

All effects of an attack are finished before KO's are resolved.
So, since the energy will have already been discarded, it's not there when the KO is taken care of and the Pokemon will be discarded.

The attacker gets to choose what energy to discard.