Withermoore's quest completed for me, got 5600xp for it.
The signet quest is for after you get off the island, which is not possible during EA.
The cursed ring probably has an NPC of which can remove the curse off of fort joy.
Idk about the teleporter, I'm pretty sure once he's across that is the end and it either just doesn't update correctly or there really is more and it just doesn't work.
The dragon you need to talk to him, smash pillars, talk to him, agree to find the witch, kill her, bring him the wand, quest succeed.
