Q1: Can I activate this card’s inherited effect even if my opponent's Digimon and the Digimon that has this card in its digivolution cards are deleted at the same timing?
No, you can't activate it.
Lv.3 Guilmon (X Antibody) EX8-009 R Rookie | Virus | Dark Dragon/X Antibody [Digivolve] [Gigimon]/[Guilmon]: Cost 0 [On Play] [When Digivolving] Reveal the top 3 cards of your deck. Add 1 card with [Growlmon] or [Gallantmon] in its name and 1 [X Antibody] among them to the hand. Return the rest to the bottom of the deck. --- Inherited: [Your Turn] [Once Per Turn] When any of your opponent's Digimon are deleted, gain 1 memory.
Lv.3 Guilmon (X Antibody) EX8-009 R Rookie | Virus | Dark Dragon/X Antibody [Digivolve] [Gigimon]/[Guilmon]: Cost 0 [On Play] [When Digivolving] Reveal the top 3 cards of your deck. Add 1 card with [Growlmon] or [Gallantmon] in its name and 1 [X Antibody] among them to the hand. Return the rest to the bottom of the deck. --- Inherited: [Your Turn] [Once Per Turn] When any of your opponent's Digimon are deleted, gain 1 memory.
Lv.3 Guilmon (X Antibody) EX8-009 R Rookie | Virus | Dark Dragon/X Antibody [Digivolve] [Gigimon]/[Guilmon]: Cost 0 [On Play] [When Digivolving] Reveal the top 3 cards of your deck. Add 1 card with [Growlmon] or [Gallantmon] in its name and 1 [X Antibody] among them to the hand. Return the rest to the bottom of the deck. --- Inherited: [Your Turn] [Once Per Turn] When any of your opponent's Digimon is deleted, gain 1 memory.
Lv.3 ギルモンX抗体 EX8-009 R 成長期 | ウィルス種 | 魔竜型/X抗体 「ギギモン」/「ギルモン」:コスト0 【登場時】【進化時】自分のデッキの上から3枚オープンする。その中の名称に「グラウモン」/「デュークモン」を含むカード1枚と「X抗体」1枚を手札に加える。残りはデッキの下に戻す。 --- Inherited: 【自分のターン】[ターンに1回]相手のデジモンが消滅したとき、メモリー+1。