Out old thermostat is dying and having a hard time controlling our heat so its time to upgrade and I would prefer to get a smart system of some flavor. Our main heat is currently gas fired boiler with radiators in each room, there are no automatically controlled zones so it is either on or off for the whole house. The old thermostat controls it from one location with 3 wires to communicate with the furnace/boiler. For cooling and some heating we have a Mitsubishi mini split system which has 5 zones, 4 bed rooms controlled separately and the first floor all on one. They currently controlled from the default infrared remotes which don't talk to each other and barely seem to automate temperature controls. The system can operate as a heat pump but I would like to be able to swap between the heat pumps and the furnace based on the outside conditions for efficiency gains

I would like to build this out as a system that can be responsible for the whole house to some extent and essentially get both systems talking to each other, does anyone have a good recommendation for what devices would work for this? I saw some talk that for the Mitsubishi stuff we might need "flair" thermostats? can those talk to other systems to set up wider automations for switching between them and the furnace? Should I just replace the furnace thermostat and just deal with the systems not talking to each other because that is a pipe dream? Any advice or product recs would be great.

For power I would prefer the mini split connections be 100% wireless, the one for the main furnace could have wired power if needed. For connection our house is 100% android so no Apple based devices.