I spoke with an agent who mentioned that they'd heard of investors transferring the ownership into an LLC and issuing a small amount of stock and gifting it to the tenant, such that they are legally part owners, has anyone seen this done successfully?

3) Give a gift to a family member each year to lower my AGI?

As long as you have the 3.5% down payment in verified funds (which can also be a gift), then it's all about how you structure the offer to make the numbers work. 

Your basis is still only $100K as would your son's basis if you gift it while living. 

One of my family members is buying the house, 2 other family members are gifting 66% of the funds, from there after it closes we’re going to transfer the deed to the LLC where there will be 3 partners, in which we’ll need a partnership agreement setup.

Send them a small gift card for their birthday and Christmas to show your appreciation.

Sounds more like a gift with the LLC as a nominee

Most DSCR lenders will accept unlimited gift funds so if you have someone who can gift you the money to get the loan amount down, it could work. 

@Jordan Lagrassa      Jordan,          Your father in law can simply gift the property to you at any time or add your name to the title without even having to notify the Bank (Intra-family transfer).

As Gary Keller said, "Listings are the gift from the Real Estate Gods."