Tia's father you have to kill, the not killing him isn't an option you get, it is just that if you fail too much trying to do it Tia will lose trust in you and stay with her father and become forgothisname wanita.Could I ask you , what difference does it make if we don't kill Gurtak and Tia's father .
Also , what's the alternative to not destroying the chalice.
Gurtak you can bewitch, so he will be your puppet and do as told or make a deal with him, so he will cooperate with you, if you make a deal, you get the option to forgive him for killing Marcus after ambushing Umah, making him your friend(?, then after killing Tia's father you can put Gurtak in charge of his fortress (You can also bewitch forgothisname and leave him in charge, this gives you the option to choose if you want orcs there to attack you or not).