I can only answer about the ERA part, as the how to order RMU will be decided by ICE (though I can guess you will be able to buy it from DriveTruRPG in the same way as the other books).
There will be ERA for RMU, and it will be made available as soon as possible after the books are up for sale (whenever that is
I have already completed a whole campaign using ERA for RMU using the beta rules and some of the modifications mentioned in the forum: from character creation, to combat resolution, spell casting and inventory management, all with good results.