I have a bauble case with a few baubles in it, but neither the ALL FOR ONE ring or the Elven King ring are activating them. is there something else I have to do?

sorry for letting you down, but it now just support those baubles which won’t check whether you actually equip it.
In botania, aura ring, blood pendant, cloud pendant, magnet ring, ice pendant, lava pendant, water ring, swap ring, tiny planet.
In extrabotany, exclude crown and core of god.

ah. I guess I'm still limited in terms of bauble space.