

Q1: If I don't trash 2 cards in my hand, can the part after "then" in this card's When Digivolving effect activate?
No, you can't. If you don't perform the processing specified for "by" in such an effect, the rest of the effect won't activate.
Lv.5 WereGarurumon (X Antibody) EX5-023 R Ultimate | Vaccine | Beastkin/X Antibody [When Digivolving] By trashing 2 cards in your hand, unsuspend this Digimon. Then, if [WereGarurumon] or [X Antibody] is in this Digimon's digivolution cards, you may return 1 Digimon card with [Garurumon] or [X Antibody] in its name from your trash to the hand. --- [When Attacking] [Once Per Turn] If this Digimon has [Garurumon] or [Omnimon] in its name, by trashing 1 card in your hand, unsuspend this Digimon.
Lv.5 WereGarurumon (X Antibody) EX5-023 R Ultimate | Vaccine | Beastkin/X Antibody [Digivolve] [WereGarurumon]: Cost 1 [When Digivolving] By trashing 2 cards in your hand, unsuspend this Digimon. Then, if [WereGarurumon] or [X Antibody] is in this Digimon's digivolution cards, you may return 1 Digimon card with [Garurumon] or [X Antibody] in its name from your trash to the hand. --- [When Attacking] [Once Per Turn] If this Digimon has [Garurumon] or [Omnimon] in its name, by trashing 1 card in your hand, unsuspend this Digimon.
Lv.5 WereGarurumon (X Antibody) EX5-023 R ultimate | Vaccine | Beastkin/X Antibody [Digivolve] [WereGarurumon]: Cost 1 [When Digivolving] By trashing 2 cards in your hand, unsuspend this Digimon. Then, if [WereGarurumon] or [X Antibody] is in this Digimon's digivolution cards, you may return 1 Digimon card with [Garurumon] or [X Antibody] in its name from your trash to the hand. --- [When Attacking] [Once Per Turn] If this Digimon has [Garurumon] or [Omnimon] in its name, by trashing 1 card in your hand, unsuspend this Digimon.
Lv.5 ワーガルルモンX抗体 EX5-023 R 完全体 | ワクチン種 | 獣人型/X抗体 【進化時】自分の手札を2枚破棄することで、このデジモンをアクティブにする。その後、このデジモンの進化元に「ワーガルルモン」/「X抗体」があるなら、自分のトラッシュから、名称に「ガルルモン」/「X抗体」を含むデジモンカード1枚を手札に戻せる。 --- 【アタック時】[ターンに1回]このデジモンが名称に「ガルルモン」/「オメガモン」を含むなら、自分の手札を1枚破棄することで、このデジモンをアクティブにする。