wow this was a loaded post!
the lending process is different for commercial property. they do base it more on the performance of the asset as opposed to you personal income. also you capacity to handle those units, if you have never been a landlord before your not likely going to be given funding. typically they want 25% down for commercial as well. I've seen folks get 90% LTV on small apartment complex but it wasn't their first rodeo and they had relationships with the lender.
Some things to consider is that you are responsible for a few more expenses than your standard SFH. you'll have to pay for attorney, CPA, landscaping, trash removal, and possibly pest control as well. if your considering owner financing any units off a apartment complex every unit must be individually metered.. that said you will more than likely have to do a condo conversion. can be expensive because you have to pay the county, a attorney, and architect a lot of money to get it processed.
your typically going to have higher repairs, maintenance, and vacancy with apartments because they are places that turn over more quickly compared to the desirability of a SFH. with that said the management side of have all 10 units in one place is amazing so when problems arise in different units your not driving all over the place to 10 different SFH.
I hope this helps!