It all depends on your appetite for risk.

For design, it really depends on your preference? 

Now if you want to buy and live there forever or you want a specific location or lifestyle or the amenities, might be something to consider, but not for investment....they're for living.Your best option right now depending on your income, is probably to buy at least 4bed house or 5 bedroom if you can make it work financially and rent bedrooms. 

Most hard money lenders are going to require 10 -20% down payment and then require you fund bring 10 - 20% of the rehab budget depending on your experience flipping (in your name/LLC you own), property ARV, etc.

Quote from @Bryce Nesbitt: Sure, but you can't depend as a MF owner on everyone setting their car timer to match the building needs. 

ADUs seem to be really popular in California, depending on location. 

It varies deal to deal, on one property maybe up to 65% LTV, but if you have more collateral the more likely they can make something work.For example, I've done numerous deals where we place a 2nd on 4-5 properties and the lender feels comfortable lending x amount of dollarsThese are very non traditional loans and no two will ever be the same.

The rules for each are different, and the allowable assets under Medicaid can vary by state.

Secondly a 7% rate with 1-2 points depending on LTV, FICO, DSCR, and prepayment penalty does sound fair/market standard.

I am not saying that to brag, the reason I say it is we all wish we could get into real estate at a younger age - but we are all different and depending on your level of risk, sometimes being patient is not a bad thing as its a marathon not a sprint.