The heart taker quest is recurring; whenever you get goblin hearts you can turn them in to Richard (assuming he is alive).
For the daylight robbery quest, have you ran into the ambush (south west of Lovis' tower), and decided to help either the merchants or the robbers? You get the quest reward right away, so even if you help the robbers it doesn't matter if you already cleared out the bandit camp.
If you go to the bandit camp yourself before telling Louis its location, you can use the password to enter and get a couple minor quests there.
You need to be able to transform into a dragon to get the book from a chest in a boat (which is in turn stuck in a tree), so must wait until you have the battle tower. In Broken Valley, you can wait to enter the quarry tower.
Once you know Razakel's name, you can enter the battle tower again and take the elevator up to the third floor, where Sassan will be waiting for you. Entering the summoning chamber is the point of no return, where most NPCs and quests in Broken Valley and Sentinel Island will be unavailable afterwards.
