Personally, if I was in your situation I would try to convince my parents of their ultimate goal to leave a legacy family gift to their generational offspring and my guess is that they are likely going to get much better loan terms due to their age and likely financial stability all that to say I think it is a much wiser decision to get the loan (it's rather small compared to the value of the home) get the rehab done as quickly as you can so you can start the leverage (basically making more money then the loan payment on the loan of 90K might be 1K-2K and if your rent is 3.5K then you are making overage aka Leveraging) and if you and them think of it as a family project then your parents won't have to think that they are going it all alone navigating this new adventure.

With that portion being roughly 200k, my father-in-law can't simply give us the money as there is tax on gift payments above 15k to my limited knowledge on the subject.

Well, she had to cover the gift taxes, but I didn’t take any profits.  

I would love to see a philanthropic book about leveraging real estate investing success for the good others. 

I have listened to bigger pockets and Brandon at one time gave gift cards.

If you are close, go take them a present.....holiday hamper, turkey, pumpkin, or some small gift....or have someone do it for you. 

I have heard some people have a small gift waiting for the tenants on move in day.

As long as it is seasoned, it can be a gift.

Odd gifts I know, but both were needed for the houses, so it was perfect.

I recently graduated from high school, at my graduation party I was humbled with many gifts, one of which was a $200 amazon gift card.