The cable reels serve many purposes. One is to stow wire lines to need--so you need several sizes. The other is to stow "fiber" line, also in several sizes.
All sorts of "needs" on warships. Buoy lines for anchors, lifeline repairs, rigging for painting platforms over the side; every possible lashing ro hoist or underway replenishment rigging, too. On capital ships, the rigging to plumb ammo down to magazines is mde up to order--dropping main battery ammo or powder charges can create Significant Emotional Events, and are thus avoided.
There will be lockers about the deck to stow items like shackles, eyes, shackle pins, tools, mousing lmarline and the like. Some lockers will have tackle for hoists and the like, too.
And, there's a Division Officer who will have inventoried the lot and is responsible for it all, and have to keep up with all the LPO monitoring how the Deck Apes use (& dispose of) such gear. The alos fall under the keen eyes of the Department Head, the XO, and the CO, all of whom might randomly stroll the decks and notice anything amiss.
Now, ventilators.
Generally, the propulsion plant stays the same. It's controls & instruments might change, but, generally the basic thermodynamics do not change. So the number and location of vents does not much change. Deleting a vents also typically entails having to fill in the "hole" in the armored decking the vent passes through. So, such things are generally kept in place.
Any excess in venting gets taken up for increased use as ventilation for crew quarters.
When a/c stowage hangers are displaced, it's usually to serve helo, instead, so the fuel bunker vents and filler are retained--only the machinery for catapaults is removed, typically.
Deck stuff typically remains deck stuff.