They said they weren't aware that it had sold.

If the solar could account for the heat pumps and even if we had extra that could be sold back to the grid.

There was no hard copy of the mobile home title via a DMV search.

My landlord sold the house I'm currently staying in, so I have to put my deal hunting on hold.

@William MurdenIf there is a broker involved they might have looked at the supply index but I've rarely seen brokers do that and even then I'd do my own due diligence on it.I recommend picking up a copy of the Self Storage Almanac from Mini Storage Messenger.https://www.ministoragemessenger.com/product/2018-self-storage-almanac/As far as doing your own research on the supply index, @Mark Byrge is correct.

The article points out that if the home is sold later, the IRS wants this paid back in recapture fees at standard rate of 25%, regardless of if the person is in the 15%, 25%, 28% or whatever bracket. 

Sometimes event links are copied over to biggerpockets but sometimes not. 

Or all 4 units have to be put sold together?

So each sale would be considered the start of a new exchange.If those two properties have the same owner and are sold as a portfolio under one contract it's possible to treat it as one exchange. 

When you find that target, turn around and get your San Diego property sold and then close the 1031.