Seems Fant is going to have to take a substantial salary reduction to stay with the team. He does though have additional roster value as a potential 3rd game day tight end(a role he experienced in Seattle) along with being a backup tackle. The status of Edoga and/or McDermott depends to a large extent how things unfold with Fant.
Right guard is going to be interesting between Lewis, Clark and GVR(can probably throw Levin in the mix as well). In my mind, Feeney is primarily competing for backup center against Murray. Seemingly, Feeney's central usefulness is he can be on the 46 player game day roster, and serve also as emergency guard backup - meaning the team has the option of only carrying seven O-Linemen on game day roster.
Of course, as always, the HUGE X factor is injuries