Confirming and updating quests in journal:
3) "The Tribe of Saheila"
No way to complete it without leaving the island - that's a mistake in game design.
5) "Withermoore's Soul Jar"
Quest is not closed after dealing with the Withermoore's soul jar.
If it's an issue regarding this info: Lord Withermoore will come back to you one last time to unlock the barrier door inside Braccus Rex fortress and thus mark the quest as complete
I've opened that barrier with the source, saw no Withermoore, quest is not closed.
3) is not meant to be completed on the island, so it's working as intended.
5) Withermoore only appears if you try to unlock the barrier when you don't have any source, quest completes after that. Not sure if it should close in a different manner if you don't need his help, so it could be bugged but it could also be working as intended.
