You do not need a plugin for WordPress or any CMS as long as the developer who is doing the integration is experienced in front-end and back-end solutions.
You have so many options to do what you want. Create a folder and stick the V3D webapp in the folder, renaming the .html file index.html (be sure to update the appropriate css etc. files). You can put it into an iframe. You can even put it inside a DIV.
With respect to the other features. The WordPress plugin packages code for those that don’t want or not able to program the features themselves. It is not needed. Your developer should be able to do all the things the WordPress plugin provides and integrate those into any CMS platform. If on the other hand, you don’t have a developer that has these skill sets. I am sure there are many that can be hired to do that integration for you.
If Soft8Soft were to go off and create a set of puzzles that were generic that could be called by any website to perform those functions that would be beneficial. Otherwise they are making unique code for every CMS and personally I rather they spend their time creating interactive 3D improvements to the base code they already have and leaving the integration to a specific platform to the developers….my two cents anyway.