Since ICM is down so it can't reach other managers & can't shutdown them but YES if because of some reason Standard Manager DIES & ICM is already dead Standard managers will not start. The ICM does the work of DISTRIBUTING the CONCURRENT request to standard managers. If ICM goes down the concurrent requests in standard managers will be running fine. But no new request will be assigned to the standard managers. So wait until all your concurrent requests gets completed and then bounce the concurrent managers to start your ICM.

Since ICM is down so it can't reach other managers & can't shutdown them but yes if because of some reason Standard Manager dies & ICM is already dead Standard managers will not start. The ICM does the work of distributing the concurrent request to standard managers. If ICM goes down the concurrent requests in standard managers will be running fine. But no new request will be assigned to the standard managers. So wait until all your concurrent requests gets completed and then bounce the concurrent managers to start your ICM.