Most of the time, an ADU will cost 100k just for that part and then you have to actually build the cosmetic part for an additional 40-50k. 

I actually have a few deals under 75% ARV right now.

In my experience, the good ones are expensive, typically require a subscription, and sometimes they even do a physical inspection of your premises to verify it is a legitimate person / business in US.

I actually like them because the homeowners' association (HOA) usually covers most of the insurance, and there is very little maintenance required.

Many other investors have asked themselves (and others this question) but what I believe it ultimately comes down to is what are your goals (how much money you'd like to make), are you physically able to manage it yourself and do you have the right organization and systems in place to do it on your own. 

Actually, the way you describe SubTo can be called "equity skimming".

I personally would sell the house - it's negatively cash flowing ~100/month, if you were to add in repairs/maintenance, CapEx, vacancy, rising insurance/property tax costs I would think you're actually losing more than you estimate (luckily it's new so you are on the very low end of that right now).

It's actually 60 days, win or lose.  

For a condo you can/should check the county assessor for land value  (you would apply the same allocation %, don't use their actual number listed) Also check your HOA documents.

Let's talk,DanIve actually been looking into buying a condo myself as an investment, I have a few rules, needs to be with both good hoa management & relatively cheap fee (bellow $600 a month) needs to be in area where I’m not competing against other new construction apartments, needs to be an area where even townhomes are so expensive you are not competing, I.e. upper nw, nova, Bethesda etc. needs to be 1990’s or newer in most cases.