Your decisions determine if tey will deal with you ar not, for the order you need to have had Seigfrieds help in the sewers and you will lose that after you declare Vivaldi innocent. For the dwarves you have to be friends with Zoltan Chivey and if you support the order in the swamp you lose them. It is possible to lose both as you have found out, but for me I found it was till possible to deal with the order assistant even though the order blacksmith would have nothing to do with me.