Lot's of great insights to learn from.

@Salvatore LentiniThanks for the insight!

Even if you had them sign 2 copies and hand them one right at that time, they can still claim that never happened.... short of having a notary there....or taking video or pictures as it happens..... they can claim that the event/exchange never happened.An email receipt is the most reasonable way......and hardcore would to have it sent via certified mail with a signature

Rather that give the typical "it depends, what are your goals," I will try to provide some insight.

So I would strongly discourage any change of ownership/reporting entities until the exchange is over. 

Or you may decide to stay together and combine all three again as one exchange. 

But all in all it should be a 1-2 minute email exchange once your policy is set up.

Many people automatically think electric resistance baseboards (or electrical coils in a central air-handler), but your ancillary heat could be easily fuelled with natural gas, propane, oil or another fuel.Presuming your use of "furnace" means a forced air furnace and not a boiler and hydronic heat, you have the option of adding a heat pump with an exchanger insert in the plenum of your existing ductwork.  

If you are relying on this house to purchase next one, I would suggest taking out a Line of credit on this house to purchase next hour  and renting this house for the 1031 exchange. 

Really appreciate the insight!