I have 3 copies of Griff in my deck

Griff is in play and dies so i subsequently attach to my house card.

I pick up a 2nd copy of Griff and put him into play as a character .

The above part i know is fine, my question :

1) If i control fewer attachments can i remove house Griff and put him as duplicate on in play Griff. I assume not because he would be a duplicate but wanted to check ?

2) Griff in play dies. I have fewer attachments in play. I assume that i cannot remove Griff from the house and put him in play because Griff is already dead. Is this correct ?

Thanks

Remember that putting Griff back into play is not optional. If you have fewer attachments in play, and Griff can legally be put into play, he must be.

1. Whenever a "put into play" effect is used on a unique card and you already own and control another copy in play, the "put into play" effect puts the unique card into play as a dupe. This has always been true, but FFG just got around to adding it to the FAQ recently (see FAQ section 4.2).

2. Correct. You cannot put a copy of a unique card into play if another copy of that card is in your dead pile. The "return to play" effect on the character-agenda is blocked and it stays as an agenda - no matter how many attachments you have in play.

If you played Benjen, he'd be pushed into play at the resolution of Benjen's ability assuming that you still have less attachments right?

Yes. After Benjen's passive is resolved, there is no copy of Griff in your dead pile, so the passive on the "agenda" is no longer prevented from resolving - and Griff would return to play.