@katyastein Thanks for reaching out!
That's a lot of gear to move around, sounds like you lead an adventurous life! We have a couple of bags that will come pretty close to holding all your snowboard gear, but none that quite hit all the marks. The biggest bags we have are the Thule RoundTrip Snowboard Roller Bag and the DAKINE High Roller Snowboard Bag. Both will carry two snowboards and one set of boots and have other storage areas for avy gear and/or outerwear. It looks like they only have room in the bag for one set of bindings to be installed on the boards at a time, however, you may be able to fit them in the bag not installed. Also, neither one mentions having a specific place to stash your helmet. If you look at the photos included with those products you may be able to tell if you think your helmet will fit on one end of the bag (the Thule one has a blue bag in one photo that looks similar in size to a helmet).
Hopefully this helps, thanks!