That adds a lot of context to the conversation. Here’s something to consider. IF you have asbestos in the duct insulation and you know about it, it’s mandatory that you replace it in California before sale of the house. If you don’t replace it, mandatory reporting to the buyer is required. So it causes an issue further down the road. Replacing it means that you don’t have to disclose that because it was changed out.
As for zoning. You could easily put in dampers if you wanted to when you’re changing out the duct work if you go that route. Or you could use something like Flair Vents (https://flair.co/). Thermal loss on a properly insulated system is very small, but yes it does exist. Interesting that you mention noise since I don’t hear my units at all. I would argue that newer units aren’t noisy.
To add another pro/con. Mini splits do run the risk of refrigerant leaks on the head units. Since the head unit is inside the house that could lead to poisoning. When the unit is contained outdoors it evaporates into the atmosphere.
To answer your question, the water heater I replaced was a heat pump water heater. But to be honest the heat pump sucks on those things. When it was time for the family to shower we had a routine that would put the unit into “high demand” mode which would use mostly elements anyway. The nice thing about on demand gas is that there’s no tank of water to always keep hot, even when you’re not using it.
A lot of people forget that efficiency of heat is always greater with gas. Furthermore, a lot of people who want to “save” the environment by going electric forget that most electricity comes from fossil fuel, even in California where we have one of the most progressive energy systems (California ISO - Supply). That conversion from fossil fuel to electricity then to heat is terrible compared to a clean gas heat (own solar generation is an exception of course).
Lastly, here’s something else to think about. 1 forced air unit vs 2 mini splits. That’s 2x the potential problems and 2x the annual service cost.