Hello i bought a house for 75000$ and can get a loan on it for 155,000$  My question is hypothetically if i were to only get a 20,000 Loan From the 155,000$ loan and never pay it would they foreclose on my property and i would loose it for not paying the 20,000 Loan?

Point is whatever overall monthly payment you are making on the house increases over time. 

Which is why I think house hacking is best for 90% plus of new buy and hold investors.I wrote an article on this a while back that goes into more depth and you might find that helpful: https://www.biggerpockets.com/blog/get-a-loan

I would for NOT do tree houses for liability reasons.

Purchase price: $499,990 5 bed 3 bath split level house in Hyattsville, 1875 sq ft

I understand moving out of your home and occupying a unit in a duplex may be the best financial decision but make sure it’s the best decision for your family because transitioning from a single family house to an apartment with a family of 4 is not always the easiest transition.

Things like this are why it's important to work with a professional who is well versed in real estate taxation because the "common/simple" strategies taught frequently like BRRR or house hacking actually get fairly complicated when it comes to handling it correctly. 

You are renting a home and not just a house.

I'm all for safe housing and keep up with any issues on my properties but this is insane.

I am not interested house-hacking.