If i use the enhance on seal of dousing, does the copy attack that i play have the symbols of the original attack. In which case, do i need match symbols to my character and the other cards in my card pool?

Seal of Dousing E commit: If you block this attack, you may play a card from your hand face down as a copy of this attack and as a reversal (following all restrictions and paying all costs).

Yes, it has the attack's symbols and you have to form a chain to play the card as normal.

Thats why you don't see many of TWELVE's foundations played because you still have to chain when you play a card from the opponent's discard pile.