I can't say how long security will take, but you will have to go through security when you change terminals.

If your bags are not checked through you will collect your bags when you land, then need to make your way to the airtrain and take that to the other terminal (it's free between terminals). You will then need to go through security and get to the gate.

Is two hours enough time? I think it's close. If you need to get boarding passes at JAL or pick up bags and recheck them, I think it's cutting it very close. If you just need to get you and the kids over and clear security without the bags and you are on time, you should be able to make it.