Yair Lapid's party is going to splinter into oblivion within a few years. That's the way of Israeli "center" parties. Just like Kadima disintegrated from 27 seats to 2, and before that Yosef Lapid (his father) headed Shinoi which had peaked at 15 seats and next elections got 0. And the same story repeats itself in Israel all the time.
What's going to happen is he is going to join the Netanyahu government. His underlings are going to fight over cabinet seats like dogs fighting over leftovers. Lapid himself would get a prominent high profile job, probably finance minister, which is usually a very unforgiving position.