Bibi has a beef with both of them, and has an option of making a coalition either one of them + the haredim, or with both of them, if they form a pact, bibi's options are limited to the latter.
Bennett is the lesser of the evils among the right, and Lapid is the lesser of the evils among the left (yeah yeah, I will probably get some heat for saying that). Let those two do whatever it is they want with their new political toys, as long as Bennett blocks any withdrawal from J&S; under such an arrangement, he has the power to pull the plug on the government, hopefully he does use it in such an emergency.