well, I am not sure that her words woudl not have raised an eyebrow, if she'd really been hinting at homosexuality...
Its true that Georgian and Regency societyt was in many ways very coarse - and that Victorianism was a reaction to all that.. But sitill the Bertrams were a fairly "prim and proper" family, very moral and well bred and I think that had they realised that Mary COULD have been referring to "nautical naughtiness" of a sexual kind, a shocked silence WOULD have descended. but I dont think that they did realise that. It was just "vices" in the general sense (not so sure about rears!! was that a reference to men with large bottoms who didn't do much work???"
And I think Edmund was a a bit shocked even by this milder pun.. but he overlooked it...