Unless you know a licensed contractor extremely well, have supplies already or decide to explore alternative methods for getting it done, my guess is your renovation expenses will be well north of 40k. 

If you were considering refinancing w/ an "alternative lender" (eg. non-bank/credit union), many have paused their SFR programs.

Materials, subs, labor, overhead.

I would pay him for the material and a reasonable labor cost

Alternatively, you could get a LOC on one or more of them if you don't need all of the cash right away. 

I haven't really used it but they mentioned to me before something about 1 year loan at purchase where you can bring in a contractor and appraiser, have the appraiser do an appraisal based on what contractor envisions as appropriate rehab (including what materials he/she will use). 

I was wondering if anyone is sourcing any products online such as cabinets, countertops, floors, vanities, windows, etc.? If so, do you have any recommended sites? I have seen a few and not sure which ones to trust.

Section 8 is a good alternative as most of the check comes from the government.

The Sensi alternates taking power from either the A/C power or furnace power depending.

Are you looking to get conventional financing or exploring an alternate route?