I can then calculate an After Repositioning Value (ARV), subtract a retained equity margin, then calculate the cost of a refinance loan to repay my private investors/lenders.

The seller pays the buyer's agent commission anyway, so it won't cost you anything to retain one!

If you are wanting to retain the property and can afford to do so, look at your partner as a seller and try to find the number that works for you both. 

(This helps me retain and learn info) I have also set up my Keyword Alerts and began to connect with some fellow members.

In owning commercial real estate you can buy into a syndicate or partnership and still 1031 later but must use a TIC structure so you retain the same tax id number otherwise you will be stuck with your current partners.

2) Investor #2 offered me 75% as he will retain 25% and will also fund me 100%.

For instance if you retain knowledge by reading, I too would recommend What Every Real Estate Investor Needs to Know About Cash Flow however be forewarned that it can be a very dry read, especially if you have little knowledge of the concepts.

I might even be interested in acting on your behalf as the personal representative, so you retain control. 

I must say that two of the most important qualities that you will learn and retain from college is discipline and the urge to want to know and learn more.

There's no banking issues with these 2 items and you retain much more control.Do not let the Buyer make payments.