Lets clear a few things up:
1. The press conference thing in July was NOT Jet2, it was OLT express and was cancelled because of their own financial difficulties.
2. I very much doubt that anyone except those who need to know will know much about the contract between easyJet and LPL, I also doubt that easyJet get protection on routes because Ryanair also serve a large amount of their routes.
3. easyJet can't pull out of Liverpool, and their based aircraft can't fall below 7.
4. Wizz into Manchester is just a rumour, I doubt they would do it at LPL's expense, the market is huge.
I don't think that Jet2 coming into Liverpool would have a negative effect, I think it would be more likely to kickstart a "route race" with the others (especially Ryanair and probably easyJet) expanding to get a bigger slice of the cake.
I'm pretty sure Jet2 will announce Liverpool soon. As someone else said Jet2 don't announce bases in July! We will have to wait and see...