This made me an enormous cashflow since there was initially nor mortgage (about 900/month).

Since you can get at most 75% LTV (based on the appraisal) OR the full amount of cash you put into it up front (purchase price, rehab costs if they are on your closing docs from the initial purchase, and even closing costs from the purchase), you could say that the sweet spot for DF is if 75% of the appraised value is right around your total up front costs (given that you've included rehab!)

My initial plan is to start with wholesaling and then expand into Multi families in the future.

Easier to rehab, the initial investment is lower, turn around is quicker, and and they generally easier to rent and have lower vanacies. 

That financing worked because I was initially purchasing it as a vacation home and the lower down payment was going to leave cash for renovations and furnishings.

-what an appropriate amount Of initial cash looks like As I’m likely in the same spot of many other folks new to this, I’m trying not to overthink things.

Update: After the initial post I was able to do so more research online and through the forums (where there were endless posts on the subject). 

I called the cleaning company and they said all services to the house go to the property owner of the house and that they were going to take me to court for a service my tenant initiated and I knew nothing about.

That's why i needed my sisters help initially.  

I think the point @Nathan G. was making initially was about the intrusion of our "partner" in STR into our lane of business (correct me if I got that wrong, Nathan).