To be honest, I think if you'd phrased this as "FIL/SIL are disrespectful of our parenting choices, and continue to smoke, drink and curse in front of the kids despite being repeatedly told not to", most of MDC would happily label them "toxic" and tell you to cut them out of your life. 
And that's the approach you should take, if any. Leave the name-dropping of Christ out of it, for His sake and yours. It's not a "Christian" issue to worry about your child's lungs; it's not a "Christian" quirk not to want your impressionable kiddos to hear cursing, or to have them around a drunk FIL. Those are issues of basic respect and boundaries. You may be against them because you're Christian, but your in-laws will probably take any requests in a better spirit if you don't advertise that fact.
And two of the issues I wouldn't bring up at all. Drinking is one. I cringed a bit when I saw "drinking/drunkenness" labelled as the same thing - I may be misinterpreting, but if you expect your in-laws to refrain from non-drunken drinking I think you're stepping way beyond Biblical mandates, not to mention politeness. (Of course, some people are unable to drink without getting drunk...) There is NOTHING in the Bible that implies your children would be damaged by seeing an adult having a glass of wine with dinner, or a bottle of whiskey on the pantry shelf.
Immodest dress is the other thing. It's subjective, and it's something your kids will be exposed to every time they set foot out of the house. To be honest, while I want DD to dress modestly when she's of an age where it's an issue, I'd rather she knew some women who dressed less modestly so she'll be less likely to demonise them as Sinful Streetwalkers. Heck, among fairly run-of-the-mill Christians you'll find women whose definition of modest ranges from ankle-length dirndls to short shorts.
If you have strong theological objections to my last few paragraphs and feel the need to enforce those boundaries with your inlaws, and feel the need to identify that enforcement with your religious beliefs, then all I ask is that you make it clear they are specific to your denomination. Not "because we're Christians" but "because we're Southern Baptists" (or whatever). And yes, I do try to return the courtesy with my own theological quirks.
And that's the approach you should take, if any. Leave the name-dropping of Christ out of it, for His sake and yours. It's not a "Christian" issue to worry about your child's lungs; it's not a "Christian" quirk not to want your impressionable kiddos to hear cursing, or to have them around a drunk FIL. Those are issues of basic respect and boundaries. You may be against them because you're Christian, but your in-laws will probably take any requests in a better spirit if you don't advertise that fact.
And two of the issues I wouldn't bring up at all. Drinking is one. I cringed a bit when I saw "drinking/drunkenness" labelled as the same thing - I may be misinterpreting, but if you expect your in-laws to refrain from non-drunken drinking I think you're stepping way beyond Biblical mandates, not to mention politeness. (Of course, some people are unable to drink without getting drunk...) There is NOTHING in the Bible that implies your children would be damaged by seeing an adult having a glass of wine with dinner, or a bottle of whiskey on the pantry shelf.
Immodest dress is the other thing. It's subjective, and it's something your kids will be exposed to every time they set foot out of the house. To be honest, while I want DD to dress modestly when she's of an age where it's an issue, I'd rather she knew some women who dressed less modestly so she'll be less likely to demonise them as Sinful Streetwalkers. Heck, among fairly run-of-the-mill Christians you'll find women whose definition of modest ranges from ankle-length dirndls to short shorts.
If you have strong theological objections to my last few paragraphs and feel the need to enforce those boundaries with your inlaws, and feel the need to identify that enforcement with your religious beliefs, then all I ask is that you make it clear they are specific to your denomination. Not "because we're Christians" but "because we're Southern Baptists" (or whatever). And yes, I do try to return the courtesy with my own theological quirks.
