Dear Mr. Author,
Thank you for your message and suggestion on splitting the installation.
In fact, we already considered such alternative but made our choice in favor of the only downloadable package so that "multi-browser" users could download it only once. Nevertheless, we might decide a per-browser installation if there is sufficient demand for that.
As far as distribution is concerned, e-Viewer is covered by Open CASCADE license (unless there is one specially for e-viewer). Thus, you may distribute it but please include the full license text ( http://www.opencascade.com/products/occ/license/ ) into distribution and acknowledge that you distribute a product by Open CASCADE SA as required by the license.
Best regards,
Commenter-1