Q1: I have this card in the battle area with 1 digivolution card under it. If an opponent's Digimon with 1 digivolution card under it later has 2 or more digivolution cards through digivolution or other process during their turn, can I suspend that opponent's Digimon?
Yes, it can be suspended. This card's Opponent's Turn effect affects all of your opponent's Digimon with as many or fewer digivolution cards as this Digimon.
Lv.6 Hexeblaumon EX7-023 SR Mega | Data | Magic Knight/Witchelny <Security A. +1><Iceclad> (Other than against Security Digimon, compare the number of digivolution cards instead of DP in this Digimon's battles.) [When Digivolving] Trash any 4 digivolution cards under your opponent's Digimon. Then, if your opponent has no Digimon with digivolution cards, return 1 of their Tamers to the bottom of the deck. [Opponent's Turn] None of your opponent's Digimon with as many or fewer digivolution cards as this Digimon can suspend. (Rule) Trait: Has [Ice-Snow] Type.
Lv.6 Hexeblaumon EX7-023 SR Mega | Data | Magic Knight/Witchelny <Security A. +1><Iceclad> (Other than against Security Digimon, compare the number of digivolution cards instead of DP in this Digimon's battles.) [When Digivolving] Trash any 4 digivolution cards under your opponent's Digimon. Then, if your opponent has no Digimon with digivolution cards, return 1 of their Tamers to the bottom of the deck. [Opponent's Turn] None of your opponent's Digimon with as many or fewer digivolution cards as this Digimon can suspend. (Rule) Trait: Has [Ice-Snow] Type.
Lv.6 Hexeblaumon EX7-023 SR Mega | Data | Magic Knight/Witchelny <Security A. +1> <Iceclad> [When Digivolving] Trash any 4 digivolution cards of your opponent's Digimon. Then, if your opponent has no Digimon with digivolution cards, return 1 of your opponent's Tamers to the bottom of the deck. [Opponent's Turn] None of your opponent's Digimon with as many or fewer digivolution cards as this Digimon can suspend. (Rule) Trait: Has [Ice-Snow] type.
Lv.6 ヘクセブラウモン EX7-023 SR 究極体 | データ種 | 魔法騎士型/ウィッチェルニー ≪Sアタック+1≫≪氷装≫(このデジモンのセキュリティデジモン以外とのバトルではDPではなく進化元枚数を比べる) 【進化時】相手のデジモンの進化元を選んで4枚破棄する。その後、進化元を持つ相手のデジモンがいないなら、相手のテイマー1体をデッキの下に戻す。 【相手のターン】進化元枚数がこのデジモン以下の相手のデジモン全てはレストできない。 〈ルール〉特徴:タイプ「氷雪型」を持つ。