General Comments:
1) You have proof of permission to use these images right?
2) Criteria 1: Can be used with or without Flooding and not be UP/OP. Forced combos are not as valuable to the game as voluntary combos.
Water Elemental
Typos: par -> per, lost -> lose (although "lose 1 hp, deal 2 damage to target creature" would be more normal for a card effect)
Comments:
It does not need flooding to be useful. Flooding does not make it OP. [Criteria 1 achieved]
Fairly balanced. Within +/- 1
casting cost.
Sea Wave
Reword?: "Gain +0|+1 if underwater."
Comments:
UP without flooding, possibly too powerful with flooding. [Criteria 1 failed]
Very redundant with Spark|Ball Lightning IMO.
Pryntil
Typo?: Charme -> Charm
Reword?: takes -> gains
Comments:
Compare with Warden as you flesh it out.
It has potential to synergize with Flooding in a way similar to Antimatter or Squid does.