T.K.
It sounds like you answered your own question, you just want some reassurance. I assure you - you are doing the right thing. I am not one to deprive someone there ganget - we call them wubbys - but if it leads to other destructive behaivor and he can self soothe without it, it's gotta go! My son sleeps with a stuffed puppy. Maybe you could switch him to something that he won't associate with thumb sucking.