If it’s oil though you might need to put a monitoring device on it or there’s something you can put in the system so it won’t freeze if the tenants let the oil run out and the basement goes below freezing.

Shallow lakes in Wisconsin I would have to guess will freeze over. 

I'd say make sure you have at least a 10% contingency budget allowed for any unseen freeze damage to play it safe.

They usually freeze before they get a property under contract or close.

From the perspective of someone that has lived in cooling climates for a long time, the idea of a boiler system in a place that rarely freezes is absolutely ridiculous.

See if the politicians actually wanted to improve circumstances for tenant class they would have (a) issued more tax bonding $ to increase projects (b) offered special waivers for shovel-ready projects in some form or fashion, (c) presented a special tax bond/offset to existing rental unit providers to lower or freeze rent rates..... 

The fridge stays on, but the DW is shutdown, & I do run food grade anti-freeze through the lines.

Will the heloc bank be notified of the transfer into a business LLC and freeze my heloc?

In some cases, you will get better deals if you buy when its freezing.  

What you pay can be included in the lawsuit, and it may be easier to get that back vs. freezing and rehabilitating your credit and having to try explain that every time you seek credit from now on.