As much as I love Kipleigh Brown, Yeoman Smith would be about 10 years old. (I hope she doesn't read this forum, but) she's getting a little old for that role; maybe she could play her mother. A better role would be Yeoman Cole or some new role.
I like the idea that Dax could turn up as long as the story is original and not a retread from DS9. Jewel (age 36) would be great normally but at about this time, Audrid Dax probably will be in her fifties or sixties and head of the Trill council. Maybe the producers can up the casting budget to get great female guest star.
The fact that she was head of the council would make it logical then for her to show up in any episode dealing with the Trills or the Trill homeworld. Hm.