Jewess, I agree with your last post!
Flatbush, I think one could argue that someone who isnt strict with lashon hara is worse than someone who isnt strict with tzniut. After all, someone who speaks lashon hara is harming multiple people, someone who doesnt dress properly generally harms themselves.
For a practical life thing: you should discuss kashrut with your Rabbi. As far as I understand, if you know someone is knowledgable enough and they tell you its kosher, you are supposed to believe them. I don’t ask my in-laws if the tuna they serve is dagim because they know thats the only thing I eat. If they serve it to me, I assume its kosher.
Ames, to be honest, I do act the same. I might sit a little differently based on the level of comfort of the outfit (so if its really uncomfortable, I shift around a lot). But I act the same.