These ships were designed on the principle of 'upkeep by replacement', so most of the equipment onboard was intended to be 'unplugged' or 'unbolted' and removed quickly and easily. It can be replaced without too much difficulty as well, including her engines. Her four RR Olympus Gas Turbines were removed, but then they are removed and replaced at regular intervals for servicing anyway. They weigh about 3 tonnes each and can and indeed HAVE been replaced whilst the ship is underway, in a matter of hours. The ships cruise on one engine, bringing the other three on line whenever full speed is required (eg for launching aircraft into wind) and even three engines will give close to full speed. Likewise the electronic equipment can for the most part be disconnected and removed for storage/maintenance ashore. Her type 996 radar has been removed from the mainmast but the type 1022 remains above the bridge. The three Phalanx guns have been 'unbolted' and removed, but could be reinstalled in a day if needed. The ship was decommissioned only a short while after completing a major refit so is in good material condition overall. The ancilliary equipment such as fire fighting equipment, pumps, auxillary machinery you mentioned are fairly common items throughout the fleet so those that have been removed will be reused in other ships, and likewise if the Ark was to be recommissioned other identical units can be sourced relatively easily.
'Can' is not the same as 'will' though.
'Can' is not the same as 'will' though.