Why would you have to put the tenants in a hotel over a bathroom floor replacement?

I think you are likely in way over your head in the scale of your thinking.  

The main issue with many Philly homes is the age these properties were builtThis give you 2 main concerns:1.

I work with investors from all over the world investing in these neighborhoods, doing BRRRR and long term rentals, so Medina isn't that far at all and is a great advantage to be able to be in the area to make house hacking more possible. 

I don't have a formula that I use and I'm much less concerned about cash flow than I am equity, although the potential added cash flow in your situation is a really nice bonus. 

If you decide not to utilize a 1031 and pay 30% taxes each time, after 10 transactions you’ll be left with a little bit over $2,000,000.

As you know since you're over 59.5 you can take distributions without penalties so you'll have to decide that along with your tax professional.   

Would you all recommend purchasing SFR over small MFR? 

The same $5,000 put in TBills and rolled over would net you $1,622.36 with zero risk, liquidity should you need it and no state income tax.Furthermore, I find Spark's claims dubious at best.

I own the property 100% (paid cash)  over the property ill be looking for home equity loan to buy and purchase another property,  repeat the process and start the BRRRR method.