I am the one behind the "tannhauser online" part. I agree with Miah. There is no automatism of the rules or rules content anywhere (and never was intended) so you need the basic rules and the rules for each character expansion, you have just the images and tokens there.
I intended to add the original maps to the build but reading your comment it might be better not to have them there and use just the fan created maps to avoid any legal conflict.
This way there is no chance to play any original scenario and to play the original game you would still need the box but it would somehow defeat the purpose of the game, being able to play with friends abroad, and have all the perks associated with this, imagine a campaign or set of scenarios that can be run online. A tannhauser league... whatever.
This also prompts a second thought, I could also add fan made teams like the Hellboy group or Moellers Herecitc etc it would make playtest of custom made characters and maps so much easier.
Obviously this is entirely fandom material without any money interest behind, I do own the game (if not all expansions) and I am not related to the fantasy grounds software people (I am just a user).
I think online and board are so much differnet experiences that they dont really compete, the competence would be with any video game company that had a game in mind.
I have not contacted FFG for permission, but I know that in simmilar cases other companies refrained to act as long as there is no game logic or automatism included in the software.
I hope you give it a try and give me feedback, that was the whole point of making it public :-)