It's not romantic and it's not fun and there may be some hurt feelings on both sides, but in my opinion, hammering out these kinds of things is absolutely crucial before you make that kind of commitment.  

I even will give them a $20 gift card to a local restaurant every once in awhile.

However, the property is already UAG, (my father will purchase if I fail to obtain financing) so I do not have enough time for the gift funds to be seasoned in my bank acc.

Could be a reasonable gift. % of cash flows or sales profits.

Any payments on the balance remaining from the original loan must be included in the debt-to-income ratio calculation for the refinance transaction.Note: Funds received as gifts and used to purchase the property may not be reimbursed with proceeds of the new mortgage loan.The new loan amount can be no more than the actual documented amount of the borrower's initial investment in purchasing the property plus the financing of closing costs, prepaid fees, and points on the new mortgage loan (subject to the maximum LTV, CLTV, and HCLTV ratios for the cash-out transaction based on the current appraised value)."

I start asking about various options that are going through my head...Option 1: Why can't I just sell my parent's the property for $300k with $10k in concessions to cover the closing costs and gift them the equity?

perhaps you don't know how the down payment Works in a Traditional Bank mortgage. the down payment money has to sit in your account for 3 months and you have to explain where it came from can't be a gift or come from your friends.

I tried an experiment where I wrote a handwritten thank you card and put out a welcome gift for every guest...and we still got the same number of 4 and 5 star reviews. 

THE FIVE LAWS OF GOLD from The Richest Man in Babylon by George ClasenGold flees the man who would force it to impossible earnings or who followeth the alluring advice of tricksters and schemers or who trusts it to his own inexperience and romantic desires in investment.Gold slippeth away from the man who invests it in businesses or purposes with which he is not familiar, or which are not approved by those skilled in its keep.

I would focus my attention on tenant retention, perhaps you drop off a small gift for their birthdays or a card for the holidays.