Chadley,
Here's my "take" on your situation:
You want to improve the quality of life within your home. Saving money while keeping your family warm and in hot water (DHW).
Wife is a bit leery about wether this will work out. FIL and BIL don't think it will work, and maybe afraid they could find themselves in the firewood business if you aren't around?
These things work as advertised! That's a fact.
You believe it can work and now you need to devise a plan to get all pieces in order. It is expensive up front. Hi ho hi ho! It's off to work you go! Overtime, liquidate some toys, whatever it takes to salt away the funds to get this project going. May take a year or 2.
You can use your energy in the mean time to learn how to install your system, start lining up some firewood, maybe find a splitter.
It is certainly a worthwhile project and will make YOU happy and proud of your accomplishment when you strike that first match!
Just go slow and it will work out.
Nuff motivational writing for tonight! Get er done....