Like you mentioned, frequent crashes, problems uploading photos, weird restrictions on what words can't be used, listings removed for no obvious reason. ....and, to me, the navigation/operation is very unintuitive and cumbersome.

So while Umbreall insurance will provide me protection but how do I keep liabilities [Without a LLC] restricted to one property asse.   

.- 2 floor ADU is expensive and is tough to do due to the height limit.- Most people kept their ADUs under 750sf to avoid the impact fees- For subdivision, it wouldn't be applicable in your case due to your lot size.Feel free to reach out if you like to discuss in details.

Best spots to invest in are West Akron, Highland Square, North Hill and parts of Goodyear Heights.  

^^ not a way to get around the net income for your rental, but as mentioned DTI restrictions are different from lender to lender so you might find more leeway looking into that. 

We had too much rain in the spring, so we weren’t able to set up the property in order to catch the height of house-buying.

Park rules are usually much more restrictive than even houses in HOAs because mobile homes and RVs are close together, and have older residents who are nosy and particular.

Normally, unless there are specific building code restrictions, the amount of units allowed on a lot is determined by the Floor Area Ratio. 

I understand the argument that the general public should not be restricted from investing in “highly profitable” deals, but what tends to end up being offered to unaccredited, unsophisticated investors in the “junk” end of the investment spectrum. 

There should be other options, however with an LLC and fourplex - yes, DSCR is by far most likely to be your best option unless you do the heavy lifting with local banks and credit unions (and these are increasingly not great options for this type of stuff as they move painfully slow and are under lots of regulations and restrictions)2) I haven't yet reached out local banks, but seeing the quotes from brokers makes me wondering if Banks may be better?