Good article from NAR on advantages of listing with an agent versus FSBO https://www.nar.realtor/magazine/real-estate-news/sales-mark...

There is no wrong way necessarily and every strategy will be dependent on your personal goals.At your age, I would imagine that cash flow is most important (versus focusing solely on appreciation).

Perhaps you should look into an attached ADU versus a duplex. 

However, if you are able to sell the land, you can still use the proceeds to invest in property in the location where you plan to retire.Ultimately, it's important to carefully weigh the costs and potential benefits of building a home on your current property versus selling and investing elsewhere.

The fact that are not qualified doesn't pertain to selling them the property versus selling them the LLC.

What is the difference in cashflow P/I versus I?

I personally would always rather be a big fish in a small pond versus the other way around if you know what I mean. 

Its much more achievable than 20% on an investment property. and I play the long game and rely on the equity I build versus living by the cash flow. 

Things like structure, S Corp ownership versus private, LLC versus S Corp, what’s best for flip versus long term hold, structuring purchases for max depreciation, cost segregation, and things like these. 

You should know the target investment area well enough to quickly recognize actual deals versus those that are not going to be profitable.You should then have a team in place that can quickly validate the condition of the property and give a decently accurate estimate of repairs.