In legal terms, [Tenant] is not renting a room from us, but rather a one fourth indivisible share of the entire apartment.

If it is sufficiently high, it is time to start doing the real work for the project (actual quotes, pull permits, legal, drafting etc.). 

I've just turned 18 and I don't plan on entering the real estate market until I have some money to my name but I've started planning for my future and I'd like to know if there are any sites I can get all the legal forms and information on the paperwork I need for the future? 

The $300 bonus is perfectly legal, though it does have to be run through the broker.

Is this legal or not? 

A  " handyman " that is not a legal business with insurance would be an employee of the homeowner , builders risk insurance would not cover him for workmans comp . 

Everyone has different legal needs and different personalities (even within the real estate industry). 

Or do I have a legal right to un-alter the premises?

So now you're paying annual business filing fees in at least two states and have two annual reports.Unless there is a legal reason for you to organize the LLC in another state, based on your facts and circumstances its best to organize the LLC in California from an administrative and compliance perspective, as you're not going to be able to avoid the CA $800 annual LLC tax, nor the CA Form 568 obligation either way.

my county only provides parcel number, legal description, and amount owed.