Get an estimate from a GC to get a good idea of what is required.Market Comparables: Check what similar-sized homes with finished basements or additional bedrooms are appraising for in your area.

I am an American living and working abroad; I have been in Europe for six years now!

I have recently worked with a company that has an excellent offer.

For example, an ADU is nice for a rental, but not every home buyer wants to pay a premium for an ADU on their property.This would be case by case and property dependent.

This is not even just an opinion, it's an objective reality.

If it was me, I'd look at it this way:1) Paperwork: I can hire an attorney at an hourly rate to write up a purchase contract, etc. 

None of those "notifications" they say they'll send every make it to my phone because it's not really an app, it's just a website as an app. 

@Fabio Cattolico"if I could get an out of state property for a great price and the numbers seem promising, wouldn't it be good to start off like that if I'm in a place where buying is unaffordable?"

That is tight leverage for an investment 2nd position loan.A private investor might be willing to do it, it's not going to be cheap at all & will be short-term money & will not be a line of credit to take out at your liking.What is your rate on the 1st?

The general idea is that you must acquire an interest in real property you do not already own, and since you already own the subject real property you want to build on, the transaction must be structured so that you are creating an interest in real property you do not already own (in fact, it does not yet exist).