However, most states have an exemption for when the beneficial ownership has not changed.

In today's legal world, it's always beneficial to have some type of legal documentation if things don't go as planned which happens quiet often.

Early retirement has been one of my goals since I began working and I initially decided to do it through mutual fund investing since that seemed to be a pretty safe choice.

My goal would be long-term ROI from equity building, appreciation, and tax advantages, as well as diversifying my investments (primarily TSP and mutual funds).  

I would try to work out a mutually agreeable solution.

As @Ben Leybovich suggested, using the funds from the sale to catapult you toward a better credit profile could be beneficial for you in the long run.Best of luck with whatever you decide!

I am in the process of selling my 1st piece of land and want to put profits into a account but I don't know which one will be more beneficial in the long run, Solo 401k vs Self Deferred IRA.

I will also note that there are a couple different ways to take advantage of both the 1031 and the 121 at the same time, and depending on your situation you might find another option more beneficial.

These retirement plans follow all the normal rules, but allow you to invest in what is called "Alternative Investments" these are not your common stocks, bonds and mutual funds.

My IRA mutual funds are making 7x that return each month when we consider the ratio of cash invested to return, and that's with zero management other than I log on to a website each month to see how much they've grown.