I'd be willing to bet buying an index fund would have a better return without any of the headaches. 

When you pay the invoice/expense in the AP queue (i.e. transfer funds from your operating account to the AP/CC account) it show as a payment for a specific expense/invoice?

I'm just beginning but am considering a bigger commitment in the next five years or so by accessing some or even all retirement funds to buy a building (I'm sure people have thoughts on whether or not that is a good idea!).

With a single-family, you have one property, which means fewer moving parts.If you have the funds to scale, I would recommend moving toward single-family homes, but if you're just starting out, multifamily can be a smarter choice.

May be worth it to check with a cost segregation company (depreciation) and start scouting property management companies.Someone smarter than me could probably tell you about taking a HELOC out to fund the next investment property in TN.

Finally on 5/14/2021 (day 348) the refi was closed and funded. 

As a former banker, you may be able to do a cash out refi on your existing properties to fund part or all of the purchase.

These programs often assert to guide you step-by-step through the process, provide assistance with funding, and connect you with contractors.

If the use of the funds are for business purposes, like investing in real-estate, you will have an easier chance of qualifying for a loan documentation and income wise.

In my experience it cannot be used as construction funding.