Honestly, there's no way in hell Disney is going sell a single Fox IP to another company, let alone Universal. They might be bloated by the addition of Fox properties to its already-tight schedule, but that's no way it would change their minds about selling them off. It can manage once Disney and Fox reorganize their business restructure. Disney knows their entertainment business far more than any major studio and they won't cede half of its power to anyone. After all, Fox IPs are a great addition to Disney's streaming service and Hulu, that's the main purpose behind Disney's acquisition of FOX. Universal barely have any live-action popular franchises at the moment. Jurassic World and F&F, the only two biggest Universal franchises, aren't going to last another decade. F&F might end in 2020 and after Jurassic World III in 2021, the film rights to the Jurassic Park franchise automatically reverts back to the Crichton Estate; it's the main reason why USH decided to re-theme the original JP ride based on JW instead, so they could continue as long as it should. After that, the only thing left surviving for Universal is DWA and Illumination, as well as Blumhouse Productions that produces low-budget horror movies.
I can see Universal trying to develop franchises like Mortal Engine (which I doubt it would be a BO success based on the trailer), but at the moment, it seems so bleak for the famed studio. Warner Bros. is ok, they have produced BO hits with many appealing and popular IPs like IT, Fantastic Beats, Wonder Woman, and the upcoming Aquaman movie. Sony seems to be developing steam with its Venom and Spider-Verse and Jumanji movies as well as the upcoming Zombie Land II next year, and Paramount seems to be in good shape with the Transformers and Mission Impossible movies. For Universal, especially their theme parks, it seems a bit bleak at the moment regarding their live-action blockbuster franchises for most audience to relate to.