Q1: Does this card's When Digivolving effect allow me to pay a cost of 2 even when I play a white Tamer card with a play cost of 4 or less?
Yes, that's correct.
Q2: Can I also use this card's inherited effect to switch the attack target to an unsuspended Eosmon?
Yes, you can.
Lv.4 Eosmon BT17-074 C Champion | Unknown | Unknown [Digivolve] [Morphomon]: Cost 2 [When Digivolving] If it's your turn, you may play 1 white Tamer card with a play cost of 4 or less or 1 level 5 or lower [Eosmon] from your hand for a play cost of 2. If this effect played, your opponent may play 1 Tamer card from their hand without paying the cost. --- Inherited: [Opponent's Turn] [Once Per Turn] When an opponent's Digimon attacks, you may switch the target of attack to 1 of your [Eosmon].
Lv.4 Eosmon BT17-074 C Champion | Unknown | Unknown [Digivolve] [Morphomon]: Cost 2 [When Digivolving] If it's your turn, you may play 1 white Tamer card with a play cost of 4 or less or 1 level 5 or lower [Eosmon] from your hand for a play cost of 2. If this effect played, your opponent may play 1 Tamer card from their hand without paying the cost. --- Inherited: [Opponent's Turn] [Once Per Turn] When an opponent's Digimon attacks, you may switch the target of attack to 1 of your [Eosmon].
Lv.4 Eosmon BT17-074 C Champion | Unknown | Unknown [Digivolve] [Morphomon]: Cost 2 [When Digivolving] If it's your turn, you may play 1 white Tamer card with a play cost of 4 or less or 1 level 5 or lower [Eosmon] from your hand for a cost of 2. If you do, your opponent may play 1 Tamer card from their hand without paying the cost. --- Inherited: [Opponent's Turn] [Once Per Turn] When an opponent's Digimon attacks, you may switch the attack target to 1 of your [Eosmon].
Lv.4 エオスモン BT17-074 C 成熟期 | 不明 | 不明 「モルフォモン」:コスト2 【進化時】自分のターンなら、自分の手札から、白の登場コスト4以下のテイマーカードかLv.5以下の「エオスモン」1枚を登場コスト2で登場できる。この効果で登場したなら、相手は相手の手札から、テイマーカード1枚をコストを支払わずに登場できる。 --- Inherited: 【相手のターン】[ターンに1回]相手のデジモンがアタックしたとき、アタックの対象を自分の「エオスモン」1体に変更できる。