Every room has TVR’s and ideally separate heat sensors
that is must, there’s no point having separate TRVs for each room without separate temperature sensors.
That is possible and is a question to home assistant and your presence/occupancy sensors setup
That part would require a bit of work. Either writing custom firmware or developing a lot of automations in HA. Alternatively you can use opentherm thermostat to turn your boiler into weather-dependent regulation and simply shut it down if none ogf the rooms needs heating.