For example, I mention that every adult must pay a $30 application fee, pass my credit/criminal background, make a combined income of 3x the rent, and whether or not the property accepts pets.

I use a combination of their messaging tool and direct messages/calling.

(They both shrink your pool or buyers and combining them really shrinks the pool.)Assuming you don’t plan to do a 1031 exchange you’ll also pay higher taxes if you can’t spread them over two calendar years, but not much. 

Combine that with rates that are near high for this century.  3 things could solve this 1) RE prices fall (that would be bad for me) 2) rents increase a lot without RE prices increasing similarly (this would be bad for tenants) 3) rates fall a lot.  

I have a friend who owns 10 or so units near here so we are thinking of spliting some of the cost and combining all the units together.

I'm guessing/hoping it's a combination of my screening, having a nicer than average unit and being responsive and respectful With the tenants.  

Some lenders offer this option, while others might prefer to handle each property individually.It will come down to the lender’s criteria, such as combined value, rental income (if applicable), and your financial profile. 

To avoid problems, it’s best to add these locks after the appraisal on a turnkey purchase or after the refinance is complete.Also, most DSCR lenders will assess the property’s market rent as a single unit rather than the combined rents of individual rooms.

If this is financing for a stabilized property rate carries more importance but rate combined with origination fees, pre-payment penalty and term in which you intend on keeping the loan in place are all considerations which together should help in deciding the best financing option.

My cash flow with those two paid off properties was only around $1500/month combined.