We put it back up on the rental market after just some deep cleaning, paint refresh... and listed it back up at $4100/mo just to see what happens.

I can not count how many investors I work with on a weekly or monthly basis who have a heating plant go out or water heater and are lamenting how deep that expense is going to cut them. 

It's an awfully deep rabbit hole!

tank could be leaking even if its still contains product. there is an easy paste test to determine if there is water in the tank. if water is in the tank, it could mean there are small holes allowing product to escape.should always take soil AND groundwater samples unless groundwater is deep (20 feet or more).    

He also built all the deep cabinets underneath the 4inch Live Edge slab.

I already had checks, signage, business advertising, business cards ordered and arriving, I was thigh high deep in this investment.

I don't want to be in deep water if was i am doing is illegal so i am considering to sell the property because i would't be able to pay for the mortgage by not renting out the spare rooms i don't need. if anyone can clear any of this up for me because iv been a fan of bigger pockets and was surprised to find out what i was doing had a name ( house hacking), but after this scare i much rather sell and maybe get a legit multifamily home and house hack. 

I think what you should do is try and have him mentor you and learn as much as possible about investing before jumping in so deep with other people's money.

#1:  take a deep breath

You should check it out, I do a deep dive into my deals and will have other guests on every week to talk about no money down investing.Anyway, to answer your questions.1.