It already pulls me out of the universe that Chapel, Number One, and Lwaxana all look like Majel. With all due respect to the late actress and Trek figure, I'm fine with in the Trek universe having Number One "really" look like Rebecca, Chapel "really" look like Jess Bush, and Majel being the "canonical" face of Lwaxana Troi.
And it never bothered me that Una, Chapel, and Lwaxana were played by the same person, especially since they are in different eras/centuries and never interacted with one another.
That just reduces the Chapel character to a joke (which will get tiresome very quickly, too). It's far better to make both of them fully realized independent characters so that they can be fully fleshed out without any arbitrary and stupid limitations (like never being allowed to be in the same room, or always having to explain why they look alike).
Or they could both be fleshed out regardless. And not being in the same room isn’t a limitation at all, unless you lack creativity.
It would an in-joke that’s no different than what’s on LD.