4 Owners, tax lien multi unit how should i go about this?

[Bernard Chouinard]

4 Owners of this 2 unit 3 br property.  Wow very long story will do my best to make it as short as possible. Changed the names just in case. .lol 

Owner 1: Carol, took a 2nd mortgage on her house to buy her daughter (Owner 2, Jen) and husband (owner 3, Bob) a multi unit and have Bobs mother also live in one of the units who is also Owner 4: Lori. 

Toxic relationship this is.  Poor Cindy has the mortgage but no vested interest in the property other than trying to help family out.   No one pays, no taxes were ever paid (bought in 2010) Bob/Jen now divorced.  Squatters are living in the building, bob and Lori are refusing to do much with the building. 

Town has a lien on the property now.  $31K needs to be paid to get taxes caught up plus  $900 in back water/sewer.   Town has this with their attorney to process and should be taking the property shortly. 

All 4 will lose this property regardless.  I've put an offer out there for them to give them each $1,000 to sign the deed over to me and I'll pay the back taxes.  So for under $40 I'll get this property.  Repairs are unknown at the moment so that will play a role int his of course.  But the property exterior seems good.  

My question to you BP community as this is really my first deal.  How should I approach this and what steps should I take for the process, transactions and to protect myself. 

Should I just a purchase agreement on the $1K each?  

Should I have an attorney be there for the deed signing? 

I should have more questions but I don't know what I don't know so looking for you on this.  If it matters property is located in Winchendon Massachusetts.  Not my ideal place to invest but if the numbers work then it doesn't matter to me.