While we don't have a firm date set for the beta access, in all likelihood it will take place a few months before the full release after most of the games mechanics are finalized. We are always looking for feedback and this will give us the time to make any changes to improve the game before release.
We are definitely looking into releasing DRM free builds of the game when it is released. In the event that we add this as an option, backers will of course be able to specify which distribution channel they prefer in the backer survey.
We plan on having local cooperative and versus modes available for two players. While online multiplayer is something that we are interested in, it would be a significant task to get it up and running to a polished level. However, we are still considering adding online play as a stretch goal.