Q1: This card doesn't have a level. Can I still digivolve into it and into other cards?
No. Cards that don't have levels can't be digivolved from, and you can't digivolve into this card. (Other than through special digivolutions.)
Lv.- Calumon EX2-045 R Unknown | Unknown | Unknown When you would play this card from your hand, reduce its play cost by 2 if you have [Guilmon], [Terriermon], [Renamon], or [Impmon] in play.[Your Turn] This Digimon can't attack.[Your Turn] When one of your Digimon digivolves, you may suspend this Digimon to gain 1 memory, <Draw 1> (Draw 1 card from your deck), and have 1 of your Digimon get +3000 DP for the turn.
Lv.- Calumon EX2-045 R Unknown | Unknown | Unknown When you would play this card from your hand, reduce its play cost by 2 if you have [Guilmon], [Terriermon], [Renamon], or [Impmon] in play.[Your Turn] This Digimon can't attack.[Your Turn] When one of your Digimon digivolves, you may suspend this Digimon to gain 1 memory, <Draw 1> (Draw 1 card from your deck), and have 1 of your Digimon get +3000 DP for the turn.
- Calumon EX2-045 R Unknown | Unknown | Unknown When you would play this card from your hand, reduce its play cost by 2 if you have [Guilmon], [Terriermon], [Renamon] or [Impmon] in play. [Your Turn] This Digimon can't attack. [Your Turn] When one of your Digimon digivolves, you may suspend this Digimon to gain 1 memory, <Draw 1>, and have 1 of your Digimon get +3000 DP for the turn.
Lv.- クルモン EX2-045 R 不明 | 不明 | 不明 手札のこのカードを登場させるとき、自分の「ギルモン」か「テリアモン」か「レナモン」か「インプモン」がいるなら、支払う登場コスト-2。 【自分のターン】このデジモンはアタックできない。 【自分のターン】自分のデジモンが進化したとき、このデジモンをレストさせることで、メモリー+1、≪1ドロー≫(自分のデッキからカードを1枚引く)し、このターンの間、自分のデジモン1体をDP+3000。