First deal..need help

[Joey Rivera]

I was recently contacted by a motivated seller.  Seller's mom passed away in 2013. The property was probated and he is currently the executive of estate. The property has no mortgage. There is a tax lien on the property for $137,000 because that is the amount Medicaid covered for Social Security. 

The Seller's lawyer made an arrangement with the IRS that whatever they sell the property for, the IRS gets 50% (No specified amount) and the other 50% would go to the Seller's brother. The seller only wants the last 3 yrs. of property tax he paid to keep the property current. The tax assessment for the property is $54,000. I had an agent pull the comps for the area and it came in at $145,000.

The property is a 3bd/2b 1 car garage. 1,350 sqft. From what the Seller is telling me the property is pretty distressed. There is currently a squatter in the property. Has been there since 2011. I don't think there is a contract in place. Seller hasn't been able to evict him, but says he is willing to leave once the property is under contract.

This is my first time doing an actual real estate deal. I want to make sure I don't miss a step. The Seller is highly motivated and is willing to do a fast cash offer. What would my best course of action be here? I don't want to low ball the Seller but I don't want to buy a property that needs too much work. I'm going to ask a few questions here as I am brand new to this industry. So any little bit of information is definitely appreciated.

1. When making a cash offer, do you go with the tax assessment value or do you go with the comps?

2. Once the deal is under contract, I know you have to record a memo. Where do I record a memo.? I would imagine the Seller has to be with me to get it notarized?

3. If the squatter puts up a big deal in the process, what actions can I take with a contract in place? Would I put in a contingency clause for that specific matter? 

4. When it comes to contracts, how do you make changes if needed? Are they done digitally or by pen, or does it matter? I just don't want to do anything illegal?

If any other details are needed, I will try to communicate as soon as possible.

I know a lot of this is basic but I would really appreciate any help I can get. Thank you