The Royal Five uses special spools that look like the later Royal 10 etc spool, but does not have the ribbon reverse latch (because the ribbon reverse is not automatic on the Five)  You might have difficulty tracking down the proper spools.  That's the bad news.  The good news is that Underwood spools fit straight on.  They are smaller and contain less ribbon, but work fine.

I don't think the platen is blue. Take a closer look and you'll see it's definitely black in the areas that weren't hastily wiped down with who-knows what type of cleaning product.

I've been pretty luck with eBay sellers. I did lose all of my money once to a seller in Germany who ripped me off (kept dragging me along until the file deadline had passed, kept my money, and didn't send the machine). Most recently I had a seller refuse to send the machine because the auction winning bid was less than he had paid for it. I called eBay - you can do that now - and the matter was successfully resolved (I ended up with the typewriter). Good luck and let us know how it works out.

Looks more grey - faded black - to me, but then again accurate colour rendering is so dependent on lighting and the white balance setting of a camera.