Upgrading the BIOS requires a reboot of the controller, but should be done simultaneously with the Ontap upgrade as this is a fully automatic process these days.
The BMC can be upgraded online as it is only needed for console access.
Upgrading the ESH2/4 and IOM3 disk shelf modules is non disruptive.
Upgrading AT-FCX can only be done non disruptive under the following conditions:
1. Running Ontap 7.3.2 or later
2. You are already using firmware version 37 or later on the AT-FCX modules
3. The SATA disk shelves are configured for multi path high availability (MPHA).
You will most likely also see that during the reboot after the Ontap 8 upgrade the firmware for the SAS HBA's will be automatically upgraded too. The SAS HBA firmware can't be downloaded separately.