If I have 90% equity, I can easily restructure debt or even use the property to secure cash.

@Joanne Hanson My favorite source for a beginner is Every Landlord's Legal Guide by NOLO.

Looking for guidance or to be pointed in the right direction to figure out how hard of a task is it to convert a 2 family legally into a 3-4 family in Yonkers, NY.

All the other pieces are lined up (investors, sponsors, loan broker, legal, management). 

I can go the legal route to enforce their contract but I feel like involving lawyers is not worth it, it is not worth dealing with these types of people.

I have no problem drawing up a new lease in his name only but is there anything else I need to do to show legally that the old lease has been terminated or will the new one automatically supersede the old one? 

From there I eventually switched to just searching the county records for legal issues.  

A lot of forum members are very knowledgeable in their respective fields related to real estate investing, whether that is real estate sales, wholesaling, flipping, rentals, lending, self-directed IRA and Solo 401k investing, or tax and legal guidance.The site has quite a few tools that can be helpful for new members.

They simply didn't want the property anymore due to the extensive legal issues that came with it and their father's past.

I reviewed the lease and the first part states they will take immediate legal action for failure to pay rent.