One advantage to having a separate bank account for each property is that your bank does this for you automatically.

Perhaps there is a basement with a separate entrance or an additional dwelling unit? 

Not sure how much extra the ~1100 sq ft basement would get in rent compared to just renting the main/top floor (4 br, 2.5 bath), but difficult to rent them separately here. 

There’s no real advantage to this and in fact it’s better to keep them separate for LTV, refinance and sales purposes. 

You'd be better off having a separate lease for each person.

Should I take out only the amount for the renovation and try to fund the 20% investment on the unknown second property separately or do it all in one loan?

Will send you a separate message!

I have bids from 3 contractors so far and am getting big variations between contractor quotes.Wondering what the approximate costs are in Central PA region.1) Roof replacement(including front and back porch roofs) is 22 square ( got quotes ranging from 7,000 to 13,000 $) - how much should I expect to pay2) Flooring -  approx 1700 sq.ft of LVP plank flooring after removing carpet ( from 3600$(material separate)  to 7800$( material included)- how much should I expect to pay 3) The home is grounded to plumbing i think ( its constructed in 1960s). 

The tenants are on separate leases, but responsible for the shared total monthly rent.

Each single family I bought required a separate mortgage, and closing costs for each one averaged $5000.