Posting to support the recommendations of CR2Builder. Basically every feature you listed is present in CR2Builder. It also has several more enhancements in addition to what you listed to make life easier when working with Poser files (It supports all non-compressed Poser file types, although it doesn't offer any special tools for MT5 or MC6 files AFAIK). The author speaks some english, and is receptive to questions and suggestions.

Here is a tutorial for the most recent version, 02k05. You will love CR2Builder, it's a Poser power user's dream come true :)