Any date on the next Synfire major update?

Not anytime soon. We do have a forked branch of new development that is being worked on, but there will still be 1.x updates coming. In theory this could proceed to 1.9, 1.10, 1.11, etc.

Will Synfire 2.0 be free for Synfire 1 users?

There will be a very generous grace period, that's for sure, but otherwise we have not made up our mind about the details yet.