If you need to you can release or trade Carlisle to free up some space with no cap penalty. I wouldn't bother re-signing Gallery until his contract is up....and even then I wouldn't re-sign him. You can put the tag on Seymour at the end of the year and trade him without penalty as well.
You'll have to decide on re-signing Schilens, Morrison, L. Walker, Gradkowski, G****ssell....the rest are pretty easy to let go or re-sign cheap if I remember correctly. I haven't noticed yet if it's better to sign them early or not but I think it might be based on how they perform during the season/playoffs. I always sign Z. Miller when he's got a couple of years left. Otherwise, he'll demand a huge contract when it's up since I use him so much.
I never have a problem signing my draft picks. I like to draft LB, DE, DT, CB, WR, FB, LB after the first year.