

Q1: Does "when this card would be used, reduce the cost by 1 for each Deva or Four Sovereigns trait card with a different name in your trash" include this card itself when I use it?
No, it doesn't.
Holy Beasts Great Cardinal Positions EX5-072 U Four Sovereigns While you have a Digimon with the [Deva] or [Four Sovereigns] trait, you may ignore this card's color requirements. When this card would be used, reduce the cost by 1 for each [Deva] or [Four Sovereigns] trait card with a different name in your trash. [Main] You may play 1 Digimon card with [Fanglongmon] in its name from your hand without paying the cost. --- [Security] Return 1 card with [Fanglongmon] in its name from your trash to the hand. Then, add this card to the hand.
Holy Beasts Great Cardinal Positions EX5-072 U Four Sovereigns While you have a Digimon with the [Deva] or [Four Sovereigns] trait, you may ignore this card's color requirements. When this card would be used, reduce the cost by 1 for each [Deva] or [Four Sovereigns] trait card with a different name in your trash. [Main] You may play 1 Digimon card with [Fanglongmon] in its name from your hand without paying the cost. --- [Security] Return 1 card with [Fanglongmon] in its name from your trash to the hand. Then, add this card to the hand.
Holy Beasts Great Cardinal Positions EX5-072 U Four Sovereigns While you have [Deva] or [Four Sovereigns] trait Digimon, you can ignore this card's color requirements. When this card would be used, reduce the cost by 1 for each [Deva] or [Four Sovereigns] trait card with a different name in your trash. [Main] You may play 1 Digimon card with [Fanglongmon] in its name from your hand without paying the cost. --- [Security] Return 1 card with [Fanglongmon] in its name from your trash to the hand. Then, add this card to the hand.
聖獣太極陣 EX5-072 U 四聖獣 特徴に「デーヴァ」/「四聖獣」を持つ自分のデジモンがいる間、このカードは色条件を無視できる。 このカードを使用するとき、自分のトラッシュの特徴に「デーヴァ」/「四聖獣」を持つ、名称の異なるカード1枚ごとに、支払う使用コスト-1。 【メイン】自分の手札から、名称に「ファンロンモン」を含むデジモンカード1枚をコストを支払わずに登場できる。 --- 【セキュリティ】自分のトラッシュから、名称に「ファンロンモン」を含むカード1枚を手札に戻す。その後、このカードを手札に加える。