Comment by thyristan

Yes, they are a good option, provided you get one that has a condensate drain. Always use a piped drain, never just a tray that you have to empty, make the hose wide enough and clean it every few months, because algae will clog it if you don't, and then you'll have your own privat lake. But that's basically the same as for any air conditioning.

Insulate all piping properly, the outdoor part will freeze in winter, and the indoor part will drip in summer if you don't. The best products for this are foamed rubber based. Make the insulation seamless with the right glue or tape, every opening will drip.

Add manual or automatic valves to shut off the heating loops in summer, so you don't accidentally get cold water in there. Your cold water loop might also need an extra circulation pump, depending on how you run your piping, but that's hard to say without a lot more detail.

FCUs are available in the same form factors as indoor units for refrigerant-based systems, including a thermostat remote control, e.g. https://www.sinclair-solutions.com/files/user-manual-en/fan-... . But get one from the manufacturer of your outdoor unit, so the communication lines work, e.g. so the indoor unit can instruct the outdoor unit to start/stop/regulate.