Rulings
Q1: Can I use this card's When Digivolving When Attacking effect to trash a total of 3 digivolution cards from my multiple different Digimon?
Yes, you can.
Q2: Can I trash just 2 digivolution cards for the conditions of this card's When Digivolving When Attacking effect?
No, you can't. A "by doing X" condition can't be met if only some of the required actions are performed. The conditions for this When Digivolving When Attacking effect require you to trash the specified number of digivolution cards.
Q4: Can I activate this card's End of Your Turn effect but choose to not to place cards with the Mineral or Rock trait from my trash as this Digimon's bottom digivolution cards?
No, you can't. If this card's End of Your Turn effect activates, you must place at least 1 card in digivolution cards. However, if you choose to not activate this effect, it won't activate and you don't place any cards in digivolution cards.
Data Sources
Lv.6 Pyramidimon EX8-055 SR Mega | Virus | Mineral/LIBERATOR <Fragment ≪3≫> (When this Digimon would be deleted, by trashing any 3 of its digivolution cards, it isn't deleted.) [When Digivolving] [When Attacking] By trashing any 3 digivolution cards with the [Mineral] or [Rock] trait from your Digimon, this Digimon unsuspends and gains <Security A. +1> for the turn. [End of Your Turn] [Once Per Turn] You may place up to 3 cards with the [Mineral] or [Rock] trait from your trash as this Digimon's bottom digivolution cards.
Lv.6 Pyramidimon EX8-055 SR Mega | Virus | Mineral/LIBERATOR <Fragment ≪3≫> (When this Digimon would be deleted, by trashing any 3 of its digivolution cards, it isn't deleted.) [When Digivolving] [When Attacking] By trashing any 3 digivolution cards with the [Mineral] or [Rock] trait from your Digimon, this Digimon unsuspends and gains <Security A. +1> for the turn. [End of Your Turn] [Once Per Turn] You may place up to 3 cards with the [Mineral] or [Rock] trait from your trash as this Digimon's bottom digivolution cards.
Lv.6 Pyramidimon EX8-055 SR
Mega | Virus | Mineral/LIBERATOR
{{Fragment|3}}.
[When Digivolving] [When Attacking] By trashing any 3 digivolution cards with the [Mineral] or [Rock] trait from your Digimon, this Digimon unsuspends and gains <Security A. +1> for the turn.
[End of Your Turn] [Once Per Turn] You may place up to 3 cards with the [Mineral] or [Rock] trait from your trash as this Digimon's bottom digivolution cards.Lv.6 ピラミディモン EX8-055 SR 究極体 | ウィルス種 | 鉱物型/リベレイター ≪フラグメント《3》≫（このデジモンが消滅するとき、このデジモンの進化元を選んで3枚破棄することで、消滅しない） 【進化時】【アタック時】自分のデジモンの進化元から、特徴に「鉱物型」/「鉱石型」を持つカード3枚を破棄することで、このデジモンをアクティブにし、ターン終了まで、≪Sアタック+1≫を得る。 【自分のターン終了時】[ターンに1回]自分のトラッシュから、特徴に「鉱物型」/「鉱石型」を持つカード3枚までをこのデジモンの進化元の下に置ける。