2 should be possible for Lewis, probably more. On current performance Lewis and Mercedes would have to implode at this point for Seb to come back, not impossible but there is no precedent for that.
You rate Kimi higher than Vettel? If we ignore history from 13 years ago, Kimi is the weakest driver in a fast car by a mile. I really doubt he'd beat Hulkenberg. And Bottas was unlucky not to win twice earlier in the season. It is worrying for him that he's had major mid-season slumps in both his seasons at Mercedes, however. Wouldn't bet against him getting replaced if Leclerc helps Ferrari to the WCC next season.