Things like GFCI outlets, vent fan issues, etc.Any quick advice would be tremendously appreciated!

I.e. using John's $30/psf is great, until during your renovation you realize that a previous owner only update the wiring to romex in the unfinished basement, but didn't run it to all outlets and light.  

If one tenant moves out or unexpected repairs pop up, the other property can help cushion the impact.Of course, more properties mean more responsibilities...double the maintenance and potential headaches.

Maybe assume 1 unit out of 5 has a $5,000 unexpected bill every 3 years?)

Just keep 3–6 months of reserves in case of vacancies or unexpected costs. 3.

Just make sure to include a buffer (about 10-15%) for unexpected costs, especially if you’re working on an older home.

The scenario was that a buyers agent wanted to be an impediment to closing a transaction between on the final walktrough she believed that certain outlet's needed GFCI.

This will probably be unpopular but you should save for a few more years even if you save enough for your down payment, if you are exhausting all your savings, you will struggle with any unexpected repairs.

I don’t immediately think it was due to a medical issue or some unexpected personal circumstance, even though I have been there; it’s usually more along the lines of, 'They must’ve found something unsatisfactory with the property.'

Also, be prepared for potential delays and unexpected costs, especially with long-distance renovations.