If I discard Born Aloft and then Gandalf leaves play and comes back in my hand, can I use Valiant Sacrifice and draw 2 cards?

Horn of Gondor's text has changed:
"After a character is destroyed,..."
instead of " After a character leaves play,...", hence my doubt...

Last question, can I avoid the 3 threat rising after a troll's attack, with Louis engaged in Conflict at the Carrock, if i use feint before resolving step one of the target enemy's attack during the combat phase?

The second question makes the difference between victory, the first one, and another defeat at The Carrock in my last game with all the 4 trolls engaged at the same time.Thanks for your help.

Horn of Gondor's unfortunate errata applies only to itself. Other cards that key off "leaves play" continue to work as before, including Valiant Sacrifice.

Since Feint prevents an attack, the prevented attack will not cause your threat to rise.

Yeah!, this quest kept me busy hours today, a great day with an epic end! Thx

I recommend ignoring the Horn of Gondor change anyway, unless you're using Tactics Imrahil.