DS211: Take a deep breath and don't do anything!
It's christmas time, a magic time to be a dub, and on top of that she is properly feeling guilty and conflicted for smoking. It's tough you get the blame, but it sound a bit like normal relationship dynamics.
If she really is 100% comitted to be a dub, why is she not doing everything to stop smoking when jehovah hate it? if she is 100% comitted and love the meetings, why is she not just going? if she 100% want to study the bible and the watchtower, whats stopping her? these are really good signs in my oppinion.
You can't actively "talk" her out of it. You are the best judge of what happens if you tell her you don't want to go and that's it, but I think it's a good bet she will turn off her brain and give you the cult reply, like asking if you believe it's the truth, if you don't love jehovah and bla bla bla and before you know it the elders are knocking on your door.
Instead, try to distract her. Show her you love her unconditionally. Try to make plans for the weekends to do something she would like to do and remember to tell her you love her. If things are very difficult between you, do the same with your children and be a good dad.
Have you read Steven Hassans books? for instance "Releasing the bonds"? I am not getting a kickback for plugging it all the time, but I think you would benefit from reading it. It is focused on what you should do in your situation (getting a loved one out from a cult) from a professional perspective.
I would try to probe her beliefs about the organization. Why she is doing so many "wrong" things? Don't do it when she is guilty or nagging you (ie. she is closer to her cult personality). For instance you might ask her (when she has just had a cigerette): "are you trying to quit smoking?" then talk about that for a while and slip in: "don't think jehovah care too much if someone is having a cigeratte once in a while do you?" and see what happens.
Wrt. studying the bible -- I think its the wrong fight to take. If you can, I think you should do it. Rely minimally on WT publications (ie. just don't open them) and either make it very dry and booring, or see if you can get something good out of it. As I recall, you mentioned she had a problem with the evils being done by God. So you might try to poke her a bit like if you are reading about some of the warcrimes of the old testement you could let a comment slip along the lines of: "I was thinking about this the other day, do you really think God ordered them to kill all the childrens as well?" and see what sort of response she give.
Hang in there!