There's absolutely no way that the benefit for your new relic will be based on having the old relic for that class. Longinus Zeta won't be required to get a bonus for the DRG relic. ANY Zeta will be. How can I be so sure about this? SE is dumb, yeah, but they're not dumb enough to say that the new jobs aren't allowed to get whatever bonus comes with having a Zeta as far as relic progression goes. It's more than likely just gonna require that you got the Z title, regardless what Job you got it for. If you have Excalibur Zeta, you'll get a headstart on the relics in 3.1. Maybe just on your first relic? Who knows. But it won't be tied to jobs, I'm about 90% sure.

Now watch me be wrong. D: