One other point to add is considering donating appreciated stock.

There's a high chance that you are feeling FOMO from the returns in public markets, sell your houses for a loss, pile into stocks, and then see mediocre performance while real estate heads back higher again.I see this, and similar actions, play out over and over.Personally, I'd stick with the real estate rather than selling it.

How about the currency exchange rate?

Sorry for the following Contrarian advice, but you're not a 5 year old so:The only reason to buy a personal residence (Home) is because someone is forcing you to.Usually, this person is called your Spouse (which is Latin for someone who forces you to make horrible financial decisions then criticizes you for them endlessly:)perhaps DON'T buy a home, just rent something affordable and invest the 20% or in your case 50% into the stock market (sp500 16.1% yearly return last 15 years, 11% last 50 years, 10% last 125 years)remember, your RENT is your maximum monthly housing expense, but your Mortgage is your minimum or starting monthly housing cost, it always goes up from thereI've, owned 2 personal homes, 100% appreciation in 6years on #1 and in 7 years on #2, (I timed our market perfectly both times), with 20% down and very low mortgage rates, but after honestly calculating all expenses, only made about 5-6% a year "investment wise".

For context, 4 adults and all our tech living here, we were running about $250/mo on average per month for electricity anyway... outside of summer a/c useage. so all in all, its saved me about $2k a year if i had to guesstimate for you (it stays hot here through October usually).i still owe about $23k on mine, have no intentions of selling the house. but if i decide to move out and rent the whole house out, our market would support higher rent in exchange for no electricity bill. i think you just need to decide what YOUR main benefit of having the panels are. for me it was for the house-hack, and consistent billing, despite the usage. if its strictly for property value increase, i'm not sure it would be worth it, pending your specific market. 

Also, I can 1031 exchange some of my rentals that I have had for 25+ years and defer the taxes. 

Or any other options you prefer such as a 1031 exchange?

For others, it may be diversify into stocks.

Paying cash is fine, but plan on using that equity to scale up with a cash out refi or 1031 exchange.

As expected, he recommends Roth conversion and invest in stocks.