

Q1: Can I use this card's Main effect to link a card that doesn't have Link?
No, you can't.
Q2: 2 copies of this card are in the battle area. Can I activate the Main effect on both copies of this card and link 1 Appmon trait Digimon card with the link cost reduced by a total of 4?
No, you can't. Multiple effects that link a card can't be activated at the same time.
Kazuki & Itsuki BT25-089 R App Driver/Appmon [Start of Your Main Phase] If your opponent has a Digimon, gain 1 memory. [Main] By suspending this Tamer, you may link 1 [Appmon] trait Digimon card from your hand or your Digimon's digivolution cards to 1 of your Digimon with the cost reduced by 2. [End of Your Turn] [Once Per Turn] 1 of your Digimon may app fuse into a Digimon card in the hand. --- [Security] Play this card without paying the cost.
Kazuki & Itsuki BT25-089 R App Driver/Appmon [Start of Your Main Phase] If your opponent has a Digimon, gain 1 memory. [Main] By suspending this Tamer, you may link 1 [Appmon] trait Digimon card from your hand or your Digimon's digivolution cards to 1 of your Digimon with the cost reduced by 2. [End of Your Turn] [Once Per Turn] 1 of your Digimon may app fuse into a Digimon card in the hand. --- [Security] Play this card without paying the cost.
Kazuki & Itsuki BT25-089 R App Driver/Appmon [Start of Your Main Phase] If your opponent has a Digimon, gain 1 memory. [Main] By suspending this Tamer, you may link 1 [Appmon] trait Digimon card from your hand or your Digimon's digivolution cards to 1 of your Digimon with the cost reduced by 2. [End of Your Turn] [Once Per Turn] 1 of your Digimon may app fuse into a Digimon card in the hand. --- [Security] Play this card without paying the cost.
カズキ&イツキ BT25-089 R アプリドライヴァー/アプモン 【自分のメインフェイズ開始時】相手のデジモンがいるなら、メモリー+1。 【メイン】このテイマーをレストさせることで、自分の手札かデジモンの進化元から、特徴「アプモン」を持つデジモンカード1枚を自分のデジモン1体に支払うコスト-2でリンクできる。 【自分のターン終了時】[ターン1回]自分のデジモン1体を手札のデジモンカードにアプ合体できる。 --- 【セキュリティ】このカードをコストを支払わず登場させる。