I was told to get a home under contract via the Option to Purchase contract (include a consideration fee given to the seller) and getting all signatures done with a copy given to the seller.

the place came w/ a fully liveable basement, including kitchen, shower bathroom the rooms have windows.  

Currently we have about 135 tenants, not including parents who call/email me whenever they want due to having a bunch of needy, entitled honestly 22ish year olds.   

Everything I own is in an LLC including my residence.

They need to do all their due diligence including understanding the value that will be added by the ADU, the finance options available, the consequences of adding the ADU (rent control, property taxes, rental limitations, etc), etc.Good luck

Study landlord basics, especially on what to include in your lease (going forward you will ALWAYS have a written lease).(2.5 Learn from mistakes and don't repeat them.)

I am planning to include the estimated property value and the funds that will be transferred into the business bank accounts.

Those are generally at least 1 of the following:1) Where they currently live2) Where they grew up3) Where they currently have family/friends living (if not included in #1 or #2)4) And as a last resort, an area where they like to travel/vacation frequently

Quote from @Carlos Lopes: Gross income doesn't matter.This is the number most people post, and it's 92.7% useless.What you need is NET income, meaning the money left over after all expenses, and that should include a dollar amount for your personal time spent operating the business. 

At the end of the day, you'll still need good credit, income (rental income from the property will suffice for DSCR loans), and cash to close, including a downpayment (likely 20%+).