Q1: Can I specify this Digimon itself as the Digimon to delete for this card's On Play When Digivolving effect?
Yes, you can.
Lv.5 SkullGreymon P-102 P Ultimate | Virus | Undead [On Play] [When Digivolving] By deleting 1 of your Digimon, delete 2 of your opponent's Digimon with 5000 DP or less. [On Deletion] You may play 1 purple or red level 3 Digimon card from your trash without paying the cost. --- Inherited: [On Deletion] You may play 1 purple or red level 3 Digimon card from your trash without paying the cost.
Lv.5 SkullGreymon P-102 P Ultimate | Virus | Undead [On Play] [When Digivolving] By deleting 1 of your Digimon, delete 2 of your opponent's Digimon with 5000 DP or less. [On Deletion] You may play 1 purple or red level 3 Digimon card from your trash without paying the cost. --- Inherited: [On Deletion] You may play 1 purple or red level 3 Digimon card from your trash without paying the cost.
Lv.5 SkullGreymon P-102 P Ultimate | Virus | Undead [On Play] [When Digivolving] By deleting 1 of your Digimon, delete 2 of your opponent's Digimon with 5000 DP or less. [On Deletion] You may play 1 {{Colour|purple}} or {{Colour|red}} level 3 Digimon card from your trash without paying the cost. --- Inherited: [On Deletion] You may play 1 {{Colour|red}} or {{Colour|purple}} level 3 Digimon card from your trash without paying the cost.
Lv.5 スカルグレイモン P-102 P 完全体 | ウィルス種 | アンデッド型 【登場時】【進化時】自分のデジモン1体を消滅させることで、DP5000以下の相手のデジモン2体を消滅させる。 【消滅時】自分のトラッシュから、紫か赤のLv.3のデジモンカード1枚をコストを支払わずに登場できる。 --- Inherited: 【消滅時】自分のトラッシュから、紫か赤のLv.3のデジモンカード1枚をコストを支払わずに登場できる。