Q1: Does this card's On Play When Digivolving effect trash a card from my opponent's security stack even when they have 6 or more security cards?
Yes, it does.
Lv.5 Cyberdramon BT21-024 U Ultimate | Vaccine | Cyborg [On Play] [When Digivolving] If your opponent has 5 or fewer security cards, they place 1 card from their hand as the bottom security card. Then, trash their top security card. (Rule) Trait: Has [Dragonkin] Type. --- Inherited: [Your Turn] This Digimon gets +4000 DP.
Lv.5 Cyberdramon BT21-024 U Ultimate | Vaccine | Cyborg [On Play] [When Digivolving] If your opponent has 5 or fewer security cards, they place 1 card from their hand as the bottom security card. Then, trash their top security card. (Rule) Trait: Has [Dragonkin] Type. --- Inherited: [Your Turn] This Digimon gets +4000 DP.
Lv.5 Cyberdramon BT21-024 U Ultimate | Vaccine | Cyborg [On Play] [When Digivolving] If your opponent has 5 or fewer security cards, they place 1 card from their hand as the bottom security card. Then, trash their top security card. --- Inherited: [Your Turn] This Digimon gets +4000 DP.
Lv.5 サイバードラモン BT21-024 U 完全体 | ワクチン種 | サイボーグ型 【登場時】【進化時】相手のセキュリティが5枚以下なら、相手は自身の手札1枚をセキュリティの下に置く。その後、相手のセキュリティを上から1枚破棄する。 〈ルール〉特徴:タイプ「竜人型」を持つ。 --- Inherited: 【自分のターン】このデジモンをDP+4000。