I bike to and from work in a suit every day that the weather allows it.
If it's very hot, I don't wear a jacket, but my preference is to either wear all of the parts of my suits or none at all.
I wear those leg strap things to keep my trousers away from the chain.
I don't worry too much about sweat because I'm commuting, not racing, and because I'm not out of shape. The minimal exertion from biking at a normal pace poses no more risk to my suit than the...