I feel like there's a few numbers missing to truly estimate the buy & hold strategy here over the flip exit.

The fear of missing the 45 day time frame is almost always greater than the reality of it. 

I've heard of a deal where maybe I buy the house from the owner and then the owner then becomes a tenant.I've watched so many BP and Real Estate Rookie videos, all the information is swirling in my head and I just don't want to miss out on a good deal.

I wanted to post this as I see many people do all the DD in the world and sometimes too much DD (I love it when the BPO comes back at $140k not $180k but loan balance is $50k and they want to fade/walk away) - but they miss the most important component which is this loan sale agreement.

But you appear to miss the fact that the third price in that formula is affected by location which includes school ratings.

I might have missed it, but are the properties paid for or have a mortgage? 

But, we still hire outside to make sure we don't miss anything.If we had not hired an inspector when we first started, we would have not caught countless items, and would have overpaid on every deal.If you're going to hire a property manager, and expect them to give you an objective analysis, good luck.

Let me know if I missed anything.

Its a complex process and we still miss from time to time. 

You seems to be on a conservative side, which is good, it means your project will be calculated and less likely to fail but being conservative means also missing out on opportunities based on being to hesitant.