The hallway to the bedroom side of the house and two of the 4 bedrooms is paneled with a dark wood paneling. 

A simple electric panel replacement would wipe out months of net cashflow.

We negotiated the triplex down to $78,000 and they fix the electric panel in the basement before they told us they wanted to sell them together.

When replacing or repairing the roof how does that affect the labor from the roofer with the panels in the way?

You need to know what exactly is there and if it has value (the contract, the person's electric bills past two years, and an inspection of the batteries/panels/and roof).

Purchase price: $505,000 Cash invested: $125,000 Sale price: $550,000 Performed the following renovations:-Roof replacement-Converted doorway into an open archway-Kitchen replacement including flooring and moving and running water lines-Converted window into a patio door with patio steps-Lighting & electrical panel and fixtures-Painting exterior / interior-New Gutters-Carpentry-Landscaping

The main problem is that the shower electronic control panel is locked and I am not able to unlock it to access the options. 

Check your electric panel and make sure you can upgrade to a heat pump.

Do you use solar panels ?

Have them cut an access panel so you can see it.