All the legacy flankers will be the first to die when hostility breaks out. All of the ROC F-16s have been upgraded to V standard.
The legacy flankers won't be at the tip of the spear to begin with anymore than any remaining J-7s or J-8s will.
If things were to ever reach conflict, they'd be very much second or third echelon back in terms of equivalent. But in peacetime, an available legacy Flanker still has the range and ability to do a run of the mill interception/air policing duty.
Also, are you sure about the F-16V upgrades? My understanding was that the MLU for all existing ROCAF F-16s to F-16V would only happen by end of 2023.