First, I don't expect others to tell me all of my solutions. i just want to know others' opinions on what may be the best path to my next place.To summarize, we sold my house in November and walked away with $36k.

Brent summarized it very well.

Should I create some kind of a cover-letter specifying and summarizing my objectives?

So to summarize, don't do it.

Here is a nice little blog post summarizing this idea: https://jaeminfrazer.com/blog/a-simple-explanation-of-the-be-do-have-model

I frequently have clients who ask about this, and Collin and Avery summarized my answer.  

You summarized it well: "the bank can take a $20K offer or not".

I would ask you to honestly share with the BiggerPockets community whether you rushed into this, or whether the particular plan provider you are working with was just selling services and not providing any meaningful information to assist you in your understanding of what works and what does not.To summarize, there are a few key takeaways:1) The Solo 401(k) plan format likely provides advantages to you as a self-employed realtor than the IRA based program does. 

If I train one of my guys to do the analysis that I am doing, look at the houses, summarize the info, I can probably double or triple my supply deals of deals from the mls.

If someone has a reliable resource (not some freelance reporter's "research") which conclusively and clearly summarizes these rules state-by-state - not only I will appreciate it, I will gladly pay for such resource.