The censored tag is rarely applied to non-hentai. If it is, it's usually because the work warrants censorship (ie, it's probably borderline hentai to begin with.) More often only the uncensored tag is applied if there's an appropriate version. If neither tag is applied it doesn't mean that the anime is uncensored, but it could mean that there isn't an uncensored version available.
Hentai is more straightforward, and generally always carries either tag. But there's a lot more that would get censored, usually.
As for BD versions, generally speaking they're a quality increase, just because they're presented in a higher quality media format (usually, sometimes they do a terrible job at it.) Occasionally they uncensor things or add additional scenes, but not always.