I'm might have too much faith but they FDA would lose the fight in court trying to classify an atty/tank/battery is a tobacco product. They're going to have their hands full enough as it is just with the nic part of it. I'm confident hardware simply won't be touched. It's not necessary to do it. Beyond a random battery fire (which happens all the time with other products like laptops), they pose no health hazard unless used improperly.
This process will definitely be a pick and choose the correct battles. And there's only one. The nic. The industry starts and stops there except for the few that go zero nic.
Maybe I don't have *enough* faith, but let's skip to the bottom line: Having to comply w/ proposed FDA regulations will most probably drive many small manufacturers out of business. The same result would obtain if FDA were to include "components" in certain circumstances as tobacco products and small businesses might choose to go out of business rather than incur costs of fighting FDA in court.
Also don't forget that the costs of complying will inevitably be passed on to the consumer by those manufacturers staying in production.