I don't know.
Have a nice day.
"Does it get replaced by MIBR automatically, by the fact that it's players are now in MIBR?"
Depends on the tournament, E League for example kicked them out in season 1 for changing orgs even though it was the same exact lineup.
They will have to qualify for ECS, Pro League I really don't know. As for the invites, I believe most of them MIBR will keep because it is according to the rank the roster has.
depends on the tournament organizer. apparently ESL has been "friendly" towards the SK org