The tenants still have power in the unit (i.e. other appliances and outlets are all working), but I don't want to neglect this and create a situation where a fire hazard may be present.My question is: is there any type of preventative maintenance (i.e. periodically add deox/other chemicals to support conductivity) or inspections I should be doing as landlord on the panel every so often?

You can set a reserve to prevent it from  going to cheap or at a loss. 

If you already have income and are eligible to buy real estate; your DTI will not prevent you from acquiring a house if you are purchasing a cash-flow positive investment property.

A favorite trick of sellers is that for one or two years before they put their property up for sale they stop doing any preventive maintenance, and only do the repairs that are absolutely necessary, in the cheapest way possible.  

One big key you left out that will prevent anyone from giving you accurate input is, what will the unit rent for each month?

@Daniel Mohnkern Tree roots will grow back, so as preventative measure you might want to rotor the roots on some schedule. 

I'm on that same track and think it can be good when you find a place where the housing prices are high enough to prevent a lot of purchasing and the rents are high enough to turn a profit in a 20-30% down scenario.

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In the event if a default, the second could pay off the first or work with the first lien holder to prevent getting wiped out in a trustee sale.