Beyond that, I simply avoid voluntarily putting myself in situations that might require a better than average likelihood of needing to defend myself or others. 

Ray you can still lend in CA you simply need a RE Broker to run the paper work for you so the state Is happy and they will usually want some sort of fee for their time and risk / effort.

Have you found more expensive insurance is simply "the nature of the beast", or is there a better way my broker and I can go about keeping costs down on that side?

In order to facilitate a 1033 you would sImply use those funds to either rebuild on the land, or the replacement can be a new investment propert purchase.

I'd encourage you personally to either consider a strategy that allows you to add value quickly and get out quickly (a Flip or BRRRR) if the HELOC is your current only/best option for cash, and/or to simply save up.

I simply call my broker and add the customers name to my liability policy.

If you do not close on enough of your properties to defer all tax you will simply pay the same tax you would have at the same time you would have.

Don't give names or addresses, but simply ask hypothetically. 

In your case, I would simply point out that they forgot to give a value for that space.

Seems to me whatever % you would give up would be offset by simply renting out the upstairs unit.