If they do decide to replace Cloud Cuckoo Land (and it seems likely) I can imagine it being rolled out over multiple years. They kind of did this in C Beebies Land with Octonauts and the new ride this year. Drayton Manor has done it with Thomas Land. Just re-theming Charlie would be a massive investment, particularly if they do it 'properly'. If they do re-theme Charlie it raises the question of whether they produce a new film for the lifts, or whether they go back to more like the original layout when it was Toyland Tours.
As has been discussed elsewhere, it seems a bit odd that Twirling Toadstool was closed this year, even if they are planning to redo the area. Assuming it is closed for the whole season (we don't know at this stage), then it makes you wonder whether there's a major problem with it. In this case it would need more than 'just' re-theming (although that in itself isn't cheap). Replacing the 4D cinema could be cheap. But if they do use an IP it would depend partly on whether they already have something available. I know Universals have Shrek 4D, but I wouldn't have thought they'd want their exact attraction being used in rival parks. Making a custom 4D film would be expensive, but it might be viable if they could add it in at Gardaland and Heide Park, plus a 4D cinema was on Chessington's mid term development plan. Producing a new live show would also have more cost associated with it, not to mention the ongoing cost once it's open. If they do bring in an IP presumably they'll add some rooms themed to it in the hotel, although this might come out of a different budget.
I agree with jon81uk, now Universals owns Dreamworks it seems less likely. Merlin seems to have the European license for Dreamworks, but not sure whether that limits the number of attractions they can use it in. Dream World has a Dreamworks in Australia. Universals may have pretty much exclusivity in Asia and the States. Between 2013-2015 there was a Madagascar Show at Busch Gardens, but this seems to have been discontinued.
It is rumours that Universals are considering a third park in Orlando themed to the Dreamworks properties. This may well be more speculation that fact, but it does seem plausible, and if they are planning a whole Dreamworks themed park, you'd think they'd want to curb the use of the brand elsewhere.