Motherboard: I understand the fear of DOA motherboards. The idea of doing all the work to put the computer together only to find the motherboard is DOA is horrifying...

My feeling, though, is that all motherboards have some DOAs. You just go with the one that seems to have (going by reviews) the lowest ratio of DOAs and hope for the best.
That is a good question about testing if it's DOA... there might be some tricks on Google, but I THINK you'd have to plug at least the CPU, RAM, and videocard (assuming no on-board video) to find out. That's not THAT bad to be able to test before screwing everything down.
I bought this mobo for the same reason (overall low ratio of DOAs) AND it had an IDE port for my old hard drive:
http://www.newegg.com/Product/Produc...82E16813131707. But I do recommend getting a new hard drive if yours is eight years old. They don't last forever.
RAM: I think 4 GB is the way to go, though the one you chose initially was a
really good deal. If you do get 4 GB, make sure to get a single stick of 4 GB instead of 2 x 2GB, so you can expand to the full 16 GB RAM later without having to throw out the old sticks. Actually, your initial mobo says it supports a maximum of 32 GB, so I'd recommend getting 1 x 8 GB stick if you get that mobo but those aren't available...