I would not run the cables from the service entrance to the enclosure inside conduit. I'd secure them to the attic framing members using cable D-rings, or some other cable fasteners.
From what you describe, I can't tell if the 2" conduit is needed. You'll need to open the closet drywall to install the conduit so why not install all the cables you'll need when the drywall is open?
If you have future plans to run cable, then I would run multiple smaller 1.5" (or other sized) conduit, that is within code. I doubt the 2" is kosher through your top and bottom plates, but I don't know what you have. An easy solution would be to call the AHJ.
I ran 4 runs of 2" conduit, basement to attic, inside a chase. The conduit penetrates floor and not top/bottom plates.
I like to use plastic drywall access panels in closets where I would like to preserve access. Maybe you could install 1 above and 1 below the LV enclosure, and skip the conduit?
Conduit sure does make life easier, though.
Could the conduit penetrate the ceiling of the closet, and then bend into the wall? Then, cover the conduit with a drywall soffit?
How about making the wall thicker? Bring it out a few inches, with the conduit coming into the closet in front of the existing top plate?
Whatever you decide, I foresee drywall work in your future.