Nice of you to think so and share your point of view with us, but not necessarily 5 months since last visit in the topic took place; and we'd rather read more elaborative posts from you, thank you very much.
Note that I've read somewhere that Coleman will only be killed once you visit Detective Raymond for the first time. If it is possible, finish investigating Vincent first, then all other side quests requiring Coleman before meeting Raymond. That way, the impact of his death is rather minor.
There's a quest in Act III that involves saving three groups of villagers who are supposedly gathering ingredients there. The first group is in the cave gathering sewant mushrooms (Vitriol), the second is amid a patch of beggartick plants (Hydragenum), and the third is at the former logging camp collecting white myrtle, I think (Vitriol again). That's not consistent with the quoted recipe.