In addition I was looking earlier in this forum and it said that the cap of runners was 5 for coop runs. But I saw a run that was successfully submitted that had seven people. So now I am Confused.

It is a multiplayer run. I also believe it might be less laggy in realms.

If I am speed running 100% and create the world on realms on one account and then switch accounts to play the world on an account with no acheivments. Is that legal?