The suit looks good. So does the rest, but if you don't mind some small suggestions:
Ideally the raincoat should be single-breasted, or you can even get a tan or beige lab coat, with side-pockets, that is a good facsimile (although it wouldn't do you much good if it rains). :^)
And the shoes, again what you have is better than fine, but a more authentic look would be over-the-heel, short boots. Go on Ebay (although you have to watch out for slow shippers there) and look for "chukka boots" (used). The Halloween store might also have some rubber clown hobo shoes, like with fake toes sticking out the front.
And if you want to go a little crazy or edgy, get some kind of bulging eyeball.
How about a cheap watch? Columbo mentioned watches in "A Friend in Deed" at the jewelry store. While on the case, he also was looking for a cheap band for his watch.
You will also need the Peugot, if you can find one.