Check with your lease and State laws but I attempt to take a proactive approach to avoid insufficient notice:Proactive - at least 60 days before the lease is set to expire I sent out a "renewal rate offer letter." 

I've tried the usual approaches, including "pay for the place you live before you pay to light the place you live" with no success. 

Any help with approaching this topic is greatly appreciated!

Here're additional guiding posts for you and food for thought: https://www.biggerpockets.com/member-blogs/10850/87253-should-i-scale-my-investment-from-single-family-homes-to-multifamilyhttps://www.biggerpockets.com/member-blogs/10850/86621-six-steps-approach-to-getting-started-in-real-estate https://www.biggerpockets.com/member-blogs/10850/85836-should-i-buy-a-turn-key-property-or-invest-in-a-syndication

If he’s in danger of losing the house I want to approach him and propose a win win strategy where I help him financially, and I end up with the house free and clear, or with him as a tenant, and me and the owner in the long run.

How do I approach the negotiation of the additional costs?

So it's definitely possible to be successful starting out with a property like this, but you are signing up for the School of Hard Knocks approach vs. getting your feet wet with something in better condition.  

Now I am being approached by a financial planner and several other people wanting me to bring some capital to several other investments like a storage facility and apartments. 

It’s fine, if this approach works for you.

Same thing if an agent approach you with their client (assuming you are going the FSBO route) Now, you still want to talk to several agents to list your house.