That is hard to answer, since I normally make my characters pretty independant, which means, they won't let themselves get influenced a lot.
Out of the basket I can think of one character that might have a different way depending on what decision Tav makes: Miss Adalind Clover, my shield dwarf clockwork sorceress. She comes from a proud family of artificer in BG and became a clockwork sorceress herself, since she developed magical talent and wanted to use it in familiar ways. She herself worked as a private detective, but her family are with the Gondians. She was investigating a murder series by Bhaalists on Orins orders (she didn't find out about Orin, just about a Bhaal cult being active again - you know: Springtime, the crazies are coming up again
) and came too close to discover the whole Absolute plot, so she got shipped away to get tadpoled and put to work.
So she pretty much is motivated to put an end to the cult, but her priorities shift a bit, when she finds out, her family is basically enslaved by Gortash to work on his steelwatchers (for more drama, her brother could be one of the hostages in the underwater prison). So her good path will be to free the Gondians, maybe help them make peace with the Ironhands on Barcus behalf and stop Gortash, orin and the whole plot. Her really evil path would be to follow a powerhungry Tav to make a pact with Gortash and take control of the brain. For the evil path, I would say, Barcus has to be dead and Tav had to put in a lot of persuasion work. Her normal way would be the good way .