-open a teades account at Sherwin Williams, lumber liquidators etc.

Your accountant files the form 8824 at the end of the year and everything is documented and your basis carried forward smoothly.

Yes, principal/interest/taxes/insurance and any HOA dues are taking in to account for the DSCR. 

I own and manage a single-family home and a 4 plex in Metro Detroit.

All you need is a competent tax accountant.

I want to put a clause in my lease concerning the charging of electric vehicles at my properties which are at present a number of single family homes in Maryland and Florida. 

After you apply for your line of credit, Amex will assign you an account manager.

Yes, it is typically normal unless there is an agreement with the accountant where you will pay him to go through all your receipts, sum up the amounts and categorize them.It is confusing from your post because it seems like originally you mentioned not having your income and expenses properly categorized but in the end you mentioned providing it to him.

Only an accountant would bring this up but it highlights one of the greatest tax strategies available.  

They're estimating $12,900 in year 1 and a steady 3.3% rent increase every single year.