Based on your problem, if this was my house, I would add some surface drainage to move most of the ponding water to another location first.

Adding the tub in my opinion adds value especially to those that may have young children, or when you need a large area to clean large items.Tub & tile- usually there is greater surface area (tub walls and ceiling) to tile so your costs of tile will go up, for the tile, the concrete backer board and the membrane.

On the stone range, it seems a pot was dropped on the surface and a crack has spread to all four corners of the stove. 

What was initially thought to be worn surface paint was in fact a build up of soap scum.

They love the lights and we pick up the tab.If you are power washing the exterior of the duplex and surrounding hard surfaces, the other tenant will likely appreciate it and be more than cooperative.

The topics were wide-spread but could have used more time to get into some details vs. surface topics.  

But a particular city within the county has experienced significantly higher rent growth than other similar cities in counties with growing populations but stagnant rents for the past 20 years (an extremely common trend in the midwest, prob not columbus though).Then there's the "that city's population declined 10%", but further investigation shows an environmental crisis caused 10% of the housing supply to be deemed uninhabitable in the area... causing a population to decrease, but a massive surge in rental demand and market rents, but not an increase in value because investors see a surface level statistic without truly understanding the market dynamics, or looking at direct indicators of an asset's performance (rental demand) instead of indirect indicators (population growth).That last situation has actually happened to me, and I managed to grab over 60 small MFR buildings at  15-20 caps over about 2 years and sell them at 10 caps.

All flooring is tile, with granite surfaces in kitchen and baths.  

Likely an uphill battle since the other three properties that adjoin the alley are owned by 2 of the complainants. 

Check the following: storm pond, storm drain, road surface and specs, sewer, water, electric, internet, road access, fire hydrant, soil compaction, setbacks.