The first coach is one that reportedly is already set to get an interview so it is worth mentioning Thad Lewis. According to ESPN's Jeremy Fowler, the Bills are expected to interview Thad Lewis.
He most recently was quarterback coach with the Tampa Bay Bucs and the job he was able to do with Baker Mayfield definitely should have him be considered for an offensive coordinator job. Last year, Mayfield had the best season in his career with over 4,000 passing yards and 28 passing touchdowns. He helped lead the Bucs to a NFC South title and a playoff berth.
Lewis played eight seasons in the NFL, including one with the Buffalo Bills in 2013, however he doesn't have much coaching experience. He was quarterback coach with the Bucs this past season but prior to that was assistant wide receiver coach for only two seasons with Tampa Bay.
This could end up being a similar situation to Ken Dorsey in terms of a coach who doesn't have any experience calling an offense and it probably makes more sense to find a veteran coach in that regards.