Peters still has two years left on his deal. I don't anticipate him not being here. It's a matter of when, not if, he'll sign a deal.
I don't expect the Bills to address the O-Line in the draft early, their first three picks will be DE, TE, OLB (not necessarily in that order). They may just add some late round O-Lineman for depth.
I think our opening day rotation will be:
Peters-Chambers-Hangartner-Butler-Walker.