Q1: If a Digimon with this card in its digivolution cards is deleted by an opponent's Retaliation, does this card's On Deletion effect activate?
Yes, it activates. Deletion by the Retaliation effect isn't considered deletion by battle.
Lv.5 Crowmon EX4-056 U Ultimate | Vaccine | Mysterious Bird [When Attacking] If you have a purple Tamer in play, this Digimon may digivolve into [Ravemon] in your hand for the digivolution cost. --- Inherited: [On Deletion] If deleted outside of a battle, delete 1 of your opponent's level 5 or lower Digimon.
Lv.5 Crowmon EX4-056 U Ultimate | Vaccine | Mysterious Bird [When Attacking] If you have a purple Tamer in play, this Digimon may digivolve into [Ravemon] in your hand for the digivolution cost. --- Inherited: [On Deletion] If deleted outside of a battle, delete 1 of your opponent's level 5 or lower Digimon.
Lv.5 Crowmon EX4-056 U Ultimate | Vaccine | Mysterious Bird [When Attacking] If you have a {{Colour|purple}} Tamer in play, this Digimon may digivolve into [Ravemon] in your hand for the digivolution cost. --- Inherited: [On Deletion] If not deleted by battle, delete 1 of your opponent's level 5 or lower Digimon.
Lv.5 ヤタガラモン EX4-056 U 完全体 | ワクチン種 | 妖鳥型 【アタック時】紫の自分のテイマーがいるなら、このデジモンを自分の手札の「レイヴモン」に進化コストを支払って進化できる。 --- Inherited: 【消滅時】このデジモンがバトル以外で消滅していたなら、Lv.5以下の相手のデジモン1体を消滅させる。