This is free money you are leaving on table if you are not at least investing up to the match. 

Also, as a passive investor, can anyone give me the broad strokes of any tax benefits they may also be entitled to similar to a solely owned piece of real estate or are those deductions pretty much off the table? 

Maybe a folding table and side by side units.

I have it listed and an offer on the table for the asking price of $129,900. 

(Normally I can do 75% LTV but the I don't have enough cash right now to come to the table with an extra $62,500)I’m having a trouble finding a lender that can go up to 80% on an investment property, any advise would be greatly appreciated.

Under normal conditions, if a broker or agent came to the table with a buyer I wouldn't begrudge paying the commission, but in this instance, she is representing herself in a private transaction.

They generally fit a different category for financing and given that you have been turned down for refinancing, odds are good a HELOC is off the table.

You still won't have a good return but you took money off the table and diversified.

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What do you bring to the table that can be a win-win part of the relationship for the mentor?