They currently own a 5 br/2ba house in which they rent out but on the same property they have an apartment building in the back 2 br/1ba and on the top level n probably can turn the bottom level Into 1br/1ba.

Is it crazy for me to purchase this building, even though cash flow checks out, due to the level of maintenance/upkeep/rehab that will be needed?

Having a basement doesn’t seem to increase the rent by that much but I will dig deeper 

Anything you find is going to be either so high level as to be meaningless or paid content to promote a particular provider. 

I'm saying to put some thought into the reinvention and don't dig a deeper hole for yourself during the process, rather dig on out of the one you are in first.

(C) Ask the tenant to buy LED bulbs that work with traditional dimmers, and live with the flickering or buzzing that may or may not occur at various light levels.

If so, you could buy a house as your primary and have someone rent a room or level of the house.

Super basic 101 level stuff like that. 

Even the administration at that level becomes a part-time job. 

Your ability to succeed out of state depends entirely on your own skill level.