Now we do 20+ flips/brrrs per year and raise money for them.

In terms of cash reserves outside of that we don't have anything substantial saved (our savings went to the earnest money) so our priority is to pay down the HELOC and increase income.

At 6-months no rent you're bleeding money. 

You could also use hard money or rental financing, but you'd need to make sure it will allow beginner investors.

Are you ok with giving someone money and losing some of the control?

CA investors still make money. 

I have sites you can purchase where we can 2x your money in less than a year all cash through zoning and entitlements.

Its easy for a contractor to spend your money and say replace things.

Aggressively pay off the mortgage and save a lot of money on interest.

thereby allowing these plumbing updates to pay for themselves).I've got the toilets and faucets all picked out (because I have personal experience with these and I know which ones are good) - but I'm not sure what to do about the shower heads...I know that shower heads are an item that can be the biggest money-saver (because these tend to consume more water than anything else).