They would. Even with the current numbers Israel still maintains Jewish majority and also the proponents of this annexation also say it'll come hand in hand with a "de-radicalization" program. There are other tools Israel can leverage (e.g. a constitution) to ensure Israel remains the Jewish homeland while making Palestinians full citizens. These don't have to contradict. Either way the Palestinians have no interest in being equal citizens in the country of Israel so it's more or less a moot point, for now.

Previous negotiations like the 2000 Camp David Summit have failed because (among other points) the right of return:

> Almost all Israeli Jews oppose a literal right of return for Palestinian refugees on the grounds that allowing such an influx of Palestinians would render Jews a minority in Israel, thus transforming Israel into an Arab-Muslim state. In addition to the right-wing and center, a majority of the Israeli left, including the far-left, opposes the right of return on these grounds.

https://en.wikipedia.org/wiki/Palestinian_right_of_return

That is correct. My scenario of annexation does not include the right of return. Israel is never going to allow that.

> then Israel would no longer be majority Jewish

It still would, as long as the Gaza strip is not also included (West Bank only).