MCC on XBOX

I’ve owned the MCC for years and come back to it every so often. I recently reinstalled it to find that j can no longer play the campaign’s because they’re being readapted again this year for the PC. I’ve seen that Halo CE has been released and maybe halo 2? However, I still can’t play them. Do I have to pay for the Reach add on to be able to play the games I already paid for? I can’t play ODST either, even though I previously paid for the add on.