It appraises for $250k so the investor (after all you can’t sell to an owner occupant, the buyer who would pay more than the investor.) has to bring 20-25% of the $250k plus all of the $50k extra.

I would sell.While I like the idea of helping out another service member, I'm not sure the math will work for the buyer. 

My friend came to me.... and I tried to get her the most I could based on what end buyer's were willing to pay How did you finance this deal?

I just had a buyer that I was representing put a FSBO under contract.

Deals with approved ADU plans are especially attractive because they offer a higher return and flexibility for future buyers, making it a prime investment opportunity.

Most firms in my market charge a transaction fee against the buyer agent's commission.

Should I look at these properties as if I were the buyer?

If they fail to leave, evict based on the habitual lease violations.If you can't figure out how to do this, or don't feel comfortable doing it, then the other option is to allow them to finish their lease and then require them to move out when it ends.

However, let's say the lender were to foreclose on an existing PadSplit, what has a larger buyer pool: (since any lender that want's to foreclose wants to make the disposition of property as seamless as possible), a standard SFR, or an SFR with multiple modified bedrooms/faux walls?

My flaw was failing to appreciate the rate cap lock and short timing.