Yeah, I think the grayed out stuff has something to do with distribution rights and regional releases. Sometimes Spotify would show me an album that I couldn't play because that version wasn't released in America, so I assume Tidal has the same issues.
It seems as though I search for something, don't find it, then two days later it's there. I don't know if these guys are just THAT good at seeing what people are looking for and they're tracking it down, or if it's a coincidence, or what, but I'm not complaining about it.
You don't need to worry about going over 16-bit, as Tidal won't do it. Tidal is meant to match CD quality, not anything above. It's just using FLAC files instead of WAV because
a) FLAC takes up less space while providing the same quality
and
b) WAV files are old as hell, so it doesn't handle meta-data and other information as well as a FLAC file, if it will even handle the information at all. When I was working on an album a few years ago, I forgot to put my information in it before I bounced all of the tracks to their final files, and it took me an hour to figure out how to put the content in there without bouncing the files again. Long story short, I ended up bouncing the files again.
Your standard 16-bit/44.1k CD's bit rate is 1,411.2 kbit/s, which is what Tidal puts out in "Hi-Fi mode". Spotify's extreme quality is 320kbit/s, which is what Tidal puts out in "Normal" mode.
It would be very cool if they put 24-bit/48k content on there, but I don't expect it yet, since it's bit rate would be about 2200kbit/s (If my guess math is right).