I'm not a lawyer nor a CPA and this comment is not a legal nor tax advice... You've been warned.
Now, after reading multiple books on the subject, consulting with multiple attorneys, I would look into the following setup that would give you the most flexibility:
Create a living trust for yourself. That will avoid probate in case of your death.
Create a single member, manager managed, LLC for each property in the state where the property is located. A registered agent will cost you around $50 per year with cheap online registered agent service (you don't need anything fancy for that as the service of registered agent is pretty basic). These LLCs will need a pretty standard asset protection/real estate oriented operating agreement. As these entities will be disregarded for tax purposes, there will be no tax filing on them.
If you want to refinance one of the property, I would suggest to do it before transferring into the LLC as you will get better offer with a personal mortgage than with a commercial one. Then after you refinanced it, transfer it to your LLC. If you are worried about the due on sale clause, create a Land Trust for the property where you are the initial beneficiary, then make a quiet assignment of beneficial interest to the LLC later on.
Create a multi-member, manager managed, holding LLC in a state like WY (great charging order protection) that will be the single member of your two LLCs.
The majority member of your holding LLC will be your living trust (ie you). Your son would be the initial minority holder.
Have your lawyer set up a strong operating agreement that will not only provide asset protection but also keep your son as a non decision maker even if his shares interest increase in the holding LLC, making you the one in control.
Every year, gift tax free to your son more interest in the holding LLC (up to the gift tax exemption fair market value).
This holding LLC will file a 1065 and issue a K1 to all members. No tax will be due by the holding LLC, but by each member individually.
Last, create a property management C corp that you will hold all shares in your living trust. This C corp will be the manager of all your LLCs. Through this corp you would be able to get fringe benefits like medical reimbursement plan, you could deduct your business related expense, you can take a salary and contribute to a pension plan, you could hire your son or other family member with lower tax bracket to offer them also other benefits.