Estimated monthly mortage/insurance/tax + loan payment would hover around $3500, not including utilities.Since we have lived in 3 ADU's in the past as tenants, we've accurately estimated that our proposed 1 bed 1 bath with fenced-off yard and pergola, ADU could rent for $1700/mo easily, with the tenant paying their own utilities.Our budget is no more than $475K, including money earmarked to repair main house (because honestly, we won't be getting anything pretty in San Fernando Valley at this price range) and construction loan for the ADU. 

With no more details there's nothing to tell you but that you're just going to have to do the math to figure out the best cash flow.

As long as you have no more than 4 financed properties you would qualify.

The new loan amount can be no more than the actual documented amount of the borrower's initial investment in purchasing the property plus the financing of closing costs, prepaid fees.

We have been putting a ton of our own money into the properties to keep them going, but at this point there is no more money to keep them afloat, so we need answers.   

I have no morals, so there is nothing to be knocked askew. 

Plus it is probably the safest bet as well with priced dropping no more than 2.9% in its history and 1.9% during housing crisis. 

Until recently (Feb 2015) there was a loop hole allowing married couples to have 10 mortgages in each name, and the first 4 for each with only 25% down, but alas no more.  

The new loan amount can be no more than the actual documented amount of the borrower's initial investment in purchasing the property plus the financing of closing costs"... 

We can not even eat at the kitchen table no more