I have a Canadian applicant, along with his American girlfriend, who want to tour the units and apply.

Just don't change your address to your parent's house, that would throw up a red flag. as long as that remains your primary and you aren't renting it out for at least a year after purchase, there shouldn't be any issues. 

My questions for you all:Is there red flags that you look when searching for a house hack deal?

They probably flag a small percentage of bogus ESA authorizations but just using them discourages bogus ESAs 2) require all ESA authorizations be AB468 compliant.  

I have all my properties with American Modern and Allstate.  

If it's wide open, that should be a red flag.

I expect rents to go up a lot because less and less Americans can afford a house over time plus folks are far more mobile now so they may be inclined to rent vs buy.

Did you know 94% of Americans don't own a single investment property? 

Unfortunately many lenders will see this as a red flag and may not take the risk to lend you the rest of the money even if you use stated income program or bank statement program but those are for self employed borrowers who have active income from their business but write off to many expenses that when filling their taxes their net income is really low or sometimes negative.

Has anyone dealt with section 8 renters before and if so what are some red flags that I should keep an eye out for?