By my very rough calculations (working on the cap going up to $165m, on a rough par with recent inflation) the Bills should have about $137.5m in cap commitments. Resulting in about $27.5m in cap space.
That's before re-signing any of Gilmore, Mills, Zach Brown, Woods, Felton, Gillislee, Bryant, Douzable, Alexander, Duke Williams, Blanton, Meeks, Schmidt.
The roster holes would be FB, #2 WR, #2/3 TE, starting RT, backup DL (x2), starting CB, backup S (x2) and punter.