While there's a natural physical resemblance between Austin Jack Lynch (Mrs. Tremond's grandson) and his father, David (Gordon Cole), I'm wondering if the similarities aren't played up on purpose. Is this yet another example of twinning in Twin Peaks?
Here's what I'm thinking:
Mrs. Tremond's grandson is "studying magic." Many TP fans consider him to be The Magician, as in, "The Magician longs to see." This makes sense, given the eyeless mask he wears.
Gordon Cole "longs to see" (find answers) as well: he leads the team investigating Blue Rose cases -- those dealing with the unexplained and supernatural. He has matured, and he can see to some degree -- consider the interaction with Phillip Jeffries -- but he is still handicapped and limited (his hearing). I'm almost wondering if such a disability is a reflection of being spirit-touched, or perhaps it increases the likelihood of inviting spirits into the material world without being near a doorway or focal area like Pearl Lake.
Some character aspects that relate to this idea:
- Agent Cooper's fascination with Tibetan Buddhism.
- The Log Lady and her log, which has served as a vessel for her husband's spirit since his death.
- Gordon Cole's insanity almost certainly made him more vulnerable to the Black Lodge.
- Major Garland Briggs is abducted (by the spirits of the White Lodge, it is believed), and told to deliver a message after being taken somewhere over the rainbow, as it were. He is shaken, and asks Betty to fix him a strong cocktail.
- The transformation of Catherine Martell, after going through fire, wandering lost in the woods, and finding herself at Pearl Lake.
Perhaps there are those who are susceptible to begin with, and contact with the Lodges leaves a mark (especially in the cases of the Log Lady and Major Briggs).
TL:DR -- I think there may be some connection between the Magician and Gordon Cole. I'm just not sure whether it is strictly symbolic, or if there's more to it, like the two worlds trying to comprehend each other.