Does ffg usually release the pdf rules after the printed once or before? how whas that i.e. with IA?

I think it will be hard to pin down when. I think Imperial Assault's rulebook was up in October, 2(?) months before release.

From the dates available on the site, December 15th was the post announcing the game would be available that week. The rules were last posted (possibly with updates from an earlier posting) on December 16th. Personally, I'm hoping for a series of tutorial videos like X-Wing had. Those were really effective in selling the game for me.