Are they going to be able to buy your proudly done flip.3) If you misjudge the market, do you know when to dump it.4) Can you put a spreadsheet together on your purchase costs, carrying costs, rehab costs, closing costs, selling costs, tax costs, contractors that don't show and delay your project etc. etc. etc.5) Is the return worth the risk.

Or sell using the 1031 exchange along with a partial 121 primary residence exemption There is a way you could take advantage of the 121 primary residence exclusion allowing you to take the first $250k of the gain tax free ($500k if married) and qualify for a 1031 exchange.Say you purchase a property as your primary residence (house hack extra rooms for extra income) and lived there for two years while stationed there.

Is your DSCR ratio greater than 1-meaning are you cash flowing (according to the lender's criteria of mortgage, property taxes and insurance (and HOA) if applicable).

After two years of occupancy, qualifying for the tax exemption, and benefiting from appreciation, we chose to sell and reinvest the funds.

If you live there 2 years or more before selling you will be exempt from tax on the 1st $250k in profit which is a nice bonus. 

On your tax return you would report the proceeds, subtract costs and proceeds paid to seller, then the remaining profit would be your flat fee.

An LLC doesn't change anything for taxes.

Especially if your son could then try to sell his primwry with the ADU under the sec 121 tax exemption I wonder if he could sell you the land?

Yes, property taxes are higher for investors but not terrible. 

Did you inherit this home with a step up in tax basis or will you need to pay taxes on any gains if you sell?