how long is "quickly" here?
Not that long at al. The ski jump would be a pre fabricated steel structure with no moving parts. QE's ski jump was fitted in a week, several smaller sections being craned into place and welded together. The JBD is completely unnecessary, neither the USN's LHA/LHDs or the RN's QEC's have them or need them, F-35Bs do not launch in full afterburner and the aft nozzle is pointed down at 45 degrees from the start of the takeoff roll to leaving the end of the ramp, so the exhaust isn't blasting at the aircraft behind, it's dispersing over the deck. On the model I put it down to artistic licence by the fanboy who conceived this carrier variant (it comes from a popular Manga in Japan). Re outfitting the workshops and stores in the hangar to maintain the F-35Bs is not particularly difficult either, no structural alterations are required, mostly new tooling for the workshops and new parts carried in the stores.
The big job would be the Thermion deck coating, it's a job that cannot be rushed as it has to be applied very carefully and slowly. Anything up to six months for the whole flight deck:
So with careful pre planning we could be looking at a conversion taking as little as 6-8 months in total. And for a ship of this size we could be looking at an air group as Jeff said of up to 16 F-35bs plus six or more helicopters. The current helicopter air group is woefully small and nowhere near capacity. These ships are on a par with the Hermes/Viraat in size, and she operated in the Falklands with an air group of twenty SHARs/Harriers plus more than ten helos:
Now I'm just waiting for the chorus of "The F-35B is twice the size of the Harrier!". Well, no it isn't. It's
twice the weight, not twice the size, there's a big difference. The USN uses a standard measure for how much space and aircraft takes up on deck, to calculate how many can be shipped relative to each other. Standard size is 1.0, a harrier is 0.89 and an F-35B is 1.1, not that much difference.
Here's a life-size mock-up of an F-25B aboard HMS Illustrious back in 2008-09 I saw it myself back then) which was used for handling trials. Revelation, it fitted on her lifts! It was tight to be sure, but as one of the officers told me back then, in rough seas they'd just load it diagonally on the lifts and it fitted much better. The Invincible's lifts had a capacity of 18 tonnes, and an F-35B unarmed and unfuelled (normal condition for an aircraft going to or from the hangar) weighs 13 tonnes. A Harrier GR7/9 is 5.7 tonnes empty and has a max take off weight of 8.25 tonnes for comparison. So 16 or so F-35Bs on a 27000tonne carrier with a sqn of helos is not a stretch by any means.
35ft= 10.66800m ... a tight fit
Problem solved!