I don't think you will be able to unlock RDM ,regardless of where the unlock quest is or the start level, without Stormblood. It's one of the advertised features of the expansion. They wouldn't just give it out for free and not announce it beforehand a la NIN.

As for an Zodiac weapon, I doubt it since they didn't do it for Ast/Mch/Drk. That being said though, they do have a bigger budget supposedly and may not be doing 3 jobs this go round. Going from 3 to 2 jobs (if that happens) and starting them at level 50 could reduce the amount of the amount of weapons that they have to model for the jobs. I'd kill if RDM got a "Save the Queen" rapier Anima weapon.