Is there a limit to the number of a particular plot twist that u can have in your deck, I.E. could I put 8 finishing moves in my deck? :confused:

There is a rule of 4 that counts for all cards except armies. You could have 4 of each version of wolverine if you want but only 4 savage beatdown or finishing move.

Below the character name is another name. If this doesn't say "Army", then only four of that character.
At present, and for the forseeable future, only army characters are unlimited, everything else is limited to four, or four per version of characters (All Wolverines- 4 Logans, 4 James Howletts, 4 New Fantastic Fours, and 4 Berserker Rages, for a total of 16 Wolverines, but different versions).

This is also a question on limits of PT cards but not on how many you can have in a deck. My question is can you play 2 of the same PT at once? Like the example I declared and attack on someone and the other player played 2 Nasty Surprises to give a +10 atk to his defender. My question is it legal to play multiplies of same PT in a combo like that?

Yes