The local store may have a limited selection but you can find more sizes and options on their website.The tenant may very well trash them, but they are inexpensive and can easily be replaced with the deposit.

Now they have come to realize that the renovation costs are much higher than expected and are looking for suckers who would be willing to pay a lot for buildings that have sat empty for years and have blight liens against them?

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.

Obviously they were most likely not deals and this would save him a lot more the a few thousand, but I would still be skeptical.  

They will likely make more off of you than you will off of them.

This fall is the best time of year to buy a house in *my opinion* because you have less competition and often more leverage than during the heat of summer.

I hear a lot of investors, realtors, and other real estate professionals saying that they are looking for vacant lots/land to build on.

Down payment assistance is a benefit for people that are lacking a lot of money. 

But to the excellent point above, for liability you should definitely go higher and it's usually not too much more expensive.

I do not want the hardwired combo (more expensive and complicated to install) - From what I've read, hardwiring is required for multi-family housing, but I don't see that it is for single family residential.