Unfortunately we've had a very cold winter here, with temps holding below freezing for weeks at a time so many of us are seeing high heating bills in general.

I intend on sending the tenant a bill for the exact repair cost as "additional rent" (per the lease) instead of evicting in the winter and deducting from the security deposit.

This will help attract more business to the state, keep it coming! 

. $800 electric bill for 800 sqft place is not uncommon.

There isn’t a per hour or per job cost to bill out.

The attorney isn't answering them so she's not sure how to get the lien removed once they pay the bill.

A key point of the LLC offering protection is the separation - so if a name/asset is in your name but the bills/loan re paid from an LLC we don't have that separation. 

Pay the bill yourself, then reimburse yourself by charging the tenants based on a formula.

You can end this by showing them an actual utility bill.

My suggestion would be to cap your utilities at a certain amount and have Tenants pay anything over that amount.That will help you manage your expenses, and also allow Tenants to gage their usage each month, and make adjustments if they don't want to go over the allotted amount.As far as collection, provide the bill showing any overages and just have them pay for it along with their rent.