There are switches in their breaker panel that directly control power in my downstairs unit.

Only after redemption rights expire (by serving specific types of notices in certain timeframes), I would then turn in my tax lien certificate to the County, and the County would issue me title as a "tax sale deed", and then I would file a 120 day notice with the County recorder, which give's anyone with unknown rights to the property at the time the tax sale deed was issued, one last shot to get their property back through legal action in Circuit Court.

My current tenant is complaining that the circuit breaker trips when they use the Microwave and toaster at the same time in the kitchen. 

He's also asking for the cost of getting permits and licensing for all of his workers, stating that he never billed us for any of this since it wasn't supposed to be needed for anything (based on what I can tell, he wasn't even planning on one for running a new power line from our breaker box to the kitchen for a double-stove).

I think it's only a couple of amps, so it doesn't need its own circuit or anything, but you need to have an outlet or junction box reasonably near the water heater.Does the closet currently have a louvered door, or vent louvers in the walls, or maybe a pipe coming down from the attic or in from outside (not the flue pipe - a separate one, just for air) to provide air for the water heater? 

I still made money, but now an HOA is a deal breaker for me.

So yes it can hurt, but it is not a deal breaker.

No-one should actually do this because it is dangerous and could kill them or the poor lineman trying to restore power if they didn't understand the inherent dangers involved.If you pulled your meter, shut off all of your circuit breakers, installed a 240v 30a plug to a double pole breaker and the neutral bus (instead of ground), then you could use a 110V generator with two extension cords to your new outlet (cords sharing neutral and having their respective hots in the 240v plug) in order to get 110v to both buses in your panel.

The house is on circuit breakers, not fuses, but according to the inspector, the house only has 50 amps coming from the street. 

In these situations, what things usually make this a deal breaker?