The seller was willing to take a secondary position on other property assets and provide a 3yr 4% interest on his loan.

An LLC when properly formed and administered provides separation and protection of assets that are outside of the LLC from the actions of the LLC.  

I would look FAR AND WIDE for someone to do an investment property HELOC -OR- go to a bunch of banks and CUs (including who you bank with now) to find someone to provide an unsecured (or secured if you have other collateral) LOC to get rid of the high int debt.

Even if one has to provide the education to some of the parties as to why a particular creative solution makes a win-win-win for all. 

If anyone has done this type of project before and has a detailed/itemized breakdown of project cost (invoice), I would truly appreciate if you can provide me with a copy and any guidance.thanks!

great advice provided - what I will add to this is if you have smokers and its not allowed I would offer to allow them out of the lease with no penalty. 

If you want to know what I coach or my program, a simple Google search will provide the information.

I provide short term rental furnishing and renovation finish list that includes paint colors, light fixtures, cabinets etc.

So @Mike S. is providing the perfect solution for you. 

Spreading funds across 2-3 properties could provide diversification and steady cash flow.