So dont use the "taxes when up" excuse with a tenant- Raising rent to market rate could prompt a tenant to move to save money.

Rents will raise and property value will increase over the long term.  

Conversely, advertising a 4/3, beautiful single family home to single traveling nurses (a pretty price-aware demographic post-Covid) may not work as well.When I go on ff.com to see what is out there in my area, I too often see units that are marketed to "everyone".

Hey Abass, I was raised here in Columbus, Ohio and have 4 doors here.

Raise your list price by the cost of the septic and market it accordingly.

As we go through the purchase process, what things should we look out for or are red flags to be aware of?

Are you aware that on some deals some lenders may require certain net worth requirements of you, and certain amounts of cash equivalents to belong to you to qualify as a borrower? 

If the seller wants to sell based on those higher rents let him/her raise them.

Anything I should be aware of and counter with if needed? 

They also like W/D install.In general, I am not aware of anything bad.