Looking at the proposed timetable. Unless that's changed, can't see GNE allowing a 20+ minute layover at Haymarket for the 355 to interwork with the 352 & 354.
However, I do note that conveniently.....the main part of the 355 times marry up with the @ xx:15 307 and @ xx:45 309 departures. So could interwork with the 307 or 309 unless the 355 will be wholly standalone with remote reliefs at Palmersville or an intentioned long 20+ minute layover at Haymarket 'just in case' given how unpredictable some parts of the 352/354/355 can be for traffic.
RE: Go North East September 2023 changes