I'm the mother of four, I've been married for 36 years..... Personally I learned a long time ago to pick your fights.... even as parents we simply can't win them all.... I'd rather worry that my kids stay away from drugs, to much booze, unsafe sex, etc..... I have a great relationship with all of them and I count it up to this way of parenting ....
but back to your question, IMO as Elvis and many others told you... their house their rules, maybe you should look for your own place.... because IMO what you are asking for isn't unsafe and it even sounds like you're trying to be adaptable and safe.... no offense but if you were mine, I'd be concerned that you'd go back to tobacco. In thinking that way, I think I'd be more open to the vaping....
BTW... I have a daughter in school working on her doctorate (she's a 4.0 yes I brag on her

), she has never smoked and NEVER allowed me to smoke in her home, now when I'm visiting her I vape and she embraces it so much, constantly trying to guess what flavor I'm using that day...She's not said this but I think it's because she worries I'll start smoking again.... I think she is now using my parenting philosophy on me
Good luck, I really hope you stay away from the tobacco
