

Q1: If I don't have both Starmons and Pickmons in my trash, does that mean I can't place any digivolution cards under the played ShootingStarmon for this card's On Deletion effect?
No, if you only have one or the other, you can place it in digivolution cards.
Lv.3 Starmons BT19-031 C Rookie | Data | Major/Xros Heart <Decoy ([Xros Heart] trait)> [On Deletion] You may play 1 [ShootingStarmon] from under your Tamers without paying the cost. Then, place 1 [Starmons] and 1 [Pickmons] from your trash as that Digimon's bottom digivolution cards. --- [When Attacking] [Once Per Turn] If this Digimon has the [Xros Heart] trait, 1 of your opponent's Digimon gets -2000 DP for the turn.
Lv.3 Starmons BT19-031 C Rookie | Data | Major/Xros Heart [Digivolve] Lv.2 w/[Xros Heart] trait: Cost 0 <Decoy ([Xros Heart] trait)> [On Deletion] You may play 1 [ShootingStarmon] from under your Tamers without paying the cost. Then, place 1 [Starmons] and 1 [Pickmons] from your trash as that Digimon's bottom digivolution cards. --- [When Attacking] [Once Per Turn] If this Digimon has the [Xros Heart] trait, 1 of your opponent's Digimon gets -2000 DP for the turn.
Lv.3 Starmons BT19-031 C rookie | Data | Major/Xros Heart [Digivolve] Lv.2 w/[Xros Heart] trait: Cost 0 <Decoy ([Xros Heart] traits)> [On Deletion] You may play 1 [ShootingStarmon] from under your Tamers without paying the cost. Then, place 1 [Starmons] and 1 [Pickmons] from your trash as that Digimon's bottom digivolution cards. --- [When Attacking] [Once Per Turn] If this Digimon has the [Xros Heart] trait, 1 of your opponent's Digimon gets -2000 DP for the turn.
Lv.3 スターモンズ BT19-031 C 成長期 | データ種 | メジャー型/クロスハート ≪デコイ《特徴「クロスハート」》≫ 【消滅時】自分のテイマーの下から、「シューティングスターモン」1枚をコストを支払わずに登場できる。その後、自分のトラッシュの「スターモンズ」と「ピックモンズ」1枚ずつをそのデジモンの進化元の下に置く。 --- 【アタック時】[ターンに1回]このデジモンが特徴に「クロスハート」を持つなら、ターン終了まで、相手のデジモン1体をDP-2000。