Stove usage will be peanuts. We had neighbours who had standard gas range (4 burners and oven) that they ran off a pair of 100 lb propane tanks. They would go weeks to months between tank trips.
Electric stoves are responsible for only about 2.8% of the typical house's electric bill.
Here, I would determine the difference by looking at my gas bills for cold months vs warm months. In the summer we go months without heating. This gives me a baseline for what the gas water heater would use. Assuming roughly equal amounts of hot water usage summer and winter, the winter gas bill - summer gas bill = winter heating use.
Right now here gas is a lot cheaper. Natural gas is about 2.25 /GJ (wholesale) to 5.50 fixed term 5 years. (or aobut 25 cents a therm for the 2.25 /GJ) Electricity is variable, but I'm currently at 8.2 c/kWh,but I pay for wire services separately.
My gas coop can only charge $1/GJ over market price.
A GJ = 277 kWh
So a GJ of electricity is roughly $22.16
Heat pumps can be more efficient. But once it gets cold outside, it has to work a lot harder. House heating with a heat pump is the better investment -- you get higher COP with smaller temperature differences. For DHW you are heating water 10-15 C hotter.
This also means that you can't use the same system to do both, without losing a lot of efficiency.
Ideally in a heat pump system you want to heat a lot of water a little bit. So where my baseboard hot water heaters use water at 60 C, while an under floor system will typically run 30 degrees cooler.
I'm reading real life numbers in zone 4 climates of overall yearly efficiencies of 2.5 to 3.5
Add to this: You have a more complex system.
If I was going to throw money at this, I would put grid connected PV on my garage roof, and sell power to the electrical company in summer and buy it back in winter. Continue to heat mostly with wood, and continue to pay my 40-6o dollar gas bill each month.