Q1: If I only have either ExVeemon or Stingmon in my hand, can I use this card?
You can use this card, but unless you place both ExVeemon and Stingmon at the bottom of your deck from your hand, you can't use this card's effect to play a Paildramon from your hand without paying its memory cost. You also can't use this card to place only ExVeemon or ExVeemon at the bottom of your deck from your hand.
DNA Digivolution - Hearts United P-022 null [Main] If you have [Davis Motomiya] and [Ken Ichijoji] in play, you may place 1 [ExVeemon] and 1 [Stingmon] from your hand at the bottom of your deck in any order to play 1 [Paildramon] from your hand without paying its memory cost. --- [Security] Add this card to your hand.
DNA Digivolution - Hearts United P-022 P [Main] If you have [Davis Motomiya] and [Ken Ichijoji] in play, you may place 1 [ExVeemon] and 1 [Stingmon] from your hand at the bottom of your deck in any order to play 1 [Paildramon] from your hand without paying its memory cost. --- [Security] Add this card to your hand.
DNA Digivolution - Hearts United P-022 P [Main] If you have [Davis Motomiya], [Ken Ichijoji] or [conj = and] in play, you may place 1 [ExVeemon] and 1 [Stingmon] from your hand at the bottom of your deck in any order to play 1 [Paildramon] from your hand without paying its memory cost. ---
ジョグレス進化 今、心をひとつに P-022 P 【メイン】自分の「本宮大輔」と「一条寺賢」がいるとき、自分の手札の「エクスブイモン」と「スティングモン」1枚ずつを好きな順番でデッキの下に戻すことで、自分の手札から、「パイルドラモン」1枚をコストを支払わずに登場させる。 --- 【セキュリティ】このカードを手札に加える。