Fantastic idea, I'd love to see it when it's finished.
As far as aesthetics go, I'd bring the vest a bit lower, and make it more vest-y/regal, just to help it suit Cheston's general fancyness. A monogrammed breast pocket would be an excellent, although time-consuming detail. I'd also prefer legitimate pants (with red and white stripes) to beech leech shorts, but that's personal preference
Other vest note: Depending on whether or not you'd like to keep the vest closer to the toy, or reality, you might want to consider making the back of the vest a different colour/texture. Although there's no reason for the colour difference in real-life vests, the back of a good vest is always made out of silk, in order to reduce friction, in turn reducing any undesirable bunching when worn with a suit jacket. Just a design aspect you might want to keep in mind.
Edit/P.S.: If you make a belt for the shorts/pants, the family jewel's jewel might make a decent motif for the buckle.
Thanks for the suggestions. It might be easier to use his default lower body model and texture, but recolored to look like your idea.