I noticed that both classes have sneak attack and trapsense. do these stack? Like if I'm a lvl 5 rogue with 3d6 of sneak attack and trapsense +1, if I start working on Divine seeker will my sneak attack go from 3d6 to 4d6 or will it stay the same? I also have 5 lvls in assassin if that makes a differnce. thank you for the help.

They should stack, yes.