I'm also considering finding a seller that would pay more than me to help my father-in-law out and perhaps get a wholesale commission that I could use on my next (ok, first) brrrr, but I'm not sure the best way to validate a fair price or know what a fair wholesale commission would be.

I am a wholesaler located in Altoona PA.

I am a realtor and wholesaler, and I get some buyers looking for owner financing, some sellers need/prefer getting cashed out and there are some lenders I work with who can provide the financing however they run out of funds sometimes.

I understand the process as follows:Step A: wholesaler places property under contract.

Business is good and we have a new law in PA that a Wholesaler has to be a licensed Real Estate Agent. 

Should I find a few buyers before I go out trying to find sellers, or should I start with sellers, then look for sellers directly or bring it to other wholesalers?

You may be better off trying to connect with some agents or other investors/wholesalers in your area and try and get off-market leads sent to you.

You can save a lot on costs if you do many repairs yourself.Look into hard money lenders or private lenders for the initial purchase and rehab.Connect with wholesalers, agents specializing in investment properties, and other BRRRR investors to find deals and learn more.

I'm a mortgage broker, so need a wholesale lender. 

Sometimes the deal is not great for their numbers, and they would still be able to wholesale the deal instead of trashing it, and get some money for more income.