Overall your math is good and the rational is good.
Other things to take in to consideration are maintenance for any of the options over the next decade or three. Not just the cost but availability of parts and competent service people for whatever equipment you end up going with.
As much as I like high efficiency and lower operating costs, I also like simplicity at the expense of efficiency. If a more efficient option will pay for itself in 5 to 10 years I will usually go for it. I also place value to equipment that I can troubleshoot and repair myself.
If you go all electric I would think PV and battery backup would be consideration as well. Even if you go a heat pump route (air or ground).
NG has an appeal, especially if power outages are common and a back generator are in the budget.
Pay close attention to air sealing and heat recovery.