Isareth the Awakener

From gatherer:
Isareth’s triggered ability goes on the stack without a target. While that ability is resolving, you may pay Variable Colorless. When you do, a second ability triggers and you pick a target creature card to return. This is different from abilities that say “If you do . . .” in that players may cast spells and activate abilities after mana is paid and the target creature card is chosen, but before that card is returned.

Isareth the Awakener

Can someone tell me if this sequencing is correct, really looking to make sure i get my triggers/priority passes down right:
-Isareteh is declared as an attacker (and becomes tapped)
-Triggered ability goes onto the stack "when ~ attacks, you may pay X..."
-pass priority to opp
-opp passes back to me
-Ability resolves, I now pay X.
-This goes on the stack, and I choose a target at this point. ("When you do...")
-pass priority to opp
-opp passes back to me
-ability resolves, target creature returns to play, and turn proceeds as normal.

Is this sequence correct on when i pay, choose targets, and all that? I just want to make sure i'm not giving info too early or choosing to pay too late to miss my window.

Bonus question, if Isareth is removed from play while the first ability is on the stack, does the second still happen?

Looks fine and ability should still resolve if hes dead.