If the gear was vibrating badly, would an RTO have been initiated?
Never having flown Concorde (sadly), this is an educated guess based on 15000 heavy jet hours (Boeing and Bus).
No, probably. A vibration with no other indications would not normally warrant a stop. My current type requires a (low speed) stop for a tyre failure but otherwise an indication on a gauge is generally required. Having said that, there’s nothing to prevent a stop call for any reason from the commander if he sees fit.