Does anyone have experience obtaining a variance for this type of usage?  

In the first quarter of 2022, the bitcoin hash rate is up 23%, while energy usage is down 25%. 

Part of me doesn't even want to mention the question of who is paying for the W/D utilities but I need a way of discussing this and making this fair given it's shared and usage could greatly vary.

A Heloc can never be used as a PITI reserve, or an asset instead its a debt burden and an additional trade line on credit.A Heloc carries a higher risk when it comes to security meaning if you miss a payment even by mistake or for any reason, your scores drop, or your balances start to change your DTI or usage percentage.

It's best to consult a tax advisor to confirm if your setup allows for cross-property PAL usage in your specific case.

Currently landlord pays for all utilities, is a system/product/device that can be installed to the water meter that tracks the usage of water through each unit so I would be able to bill the tenants separately?

If the pumper pulls out inappropriate material you can address with tenant. 

In fact, most cities will send a High Usage Warning letter.

However I would probably bill it back to the tenant monthly if it was based on usage like water.

My Zillow account was disabled today due to an inappropriate comment a made to a prospective tenant about Emotional Support Animals.