one, are you allowed,i say yes. two, you both can have same character out at same time

but can not take or control if you do,plz help not sure ty guys .and anyother rules that might apply.

1. Yes you may each have the same characters in play.

2. No, you may not take control of a unique character that you already have in play.

Core Rules, Page 9

"Each player may only have one copy of a unique card in play. Thus, you cannot put into play or take control of a unique card which you already own or control
(except for duplicates, see below). You also may not play or take control of a unique card if there is a copy of that card in your dead pile, or if your opponent has taken control of another copy of that unique card from you."

I believe in mirror matches that as long as the card is not self-referential (such as Cersei [LotR]) then you can trigger some effects off of your opponents' characters. An example would be Cersei's Attendant [core]. If your opponent's Cersei is killed then you can still trigger your Cersei's Attendant 's ability, but not if their Cersei's Attendant was killed.

I might be wrong and I'm sure someone will chime in quickly one way or the other.

Slothgodfather said:

Nope, you're right. Just like you can play Lady for free if your opponent controls Sansa Stark, but your Lady will affect his Sansa, too.