One lovely advantage of the internet is that it's all there for our lazy*, leisurely perusal if you like exploring. I use Wiki a lot for this, and can rarely fault it. Re: "rotary" - only quoting, but most would argue it starts with one Félix Millet. *speaking for myself
Correct. The Millet still exists. I have seen it, in the Musée des Arts et Métiers in Paris. The later one was German. Can you find it?
Nothing worth quoting but fascinating to read about Mr Redrup, no luck with motorcycle pictures on "his" so far either, but one specimen resides at Sammy Miller's place apparently. https://en.wikipedia.org/wiki/Charles_Benjamin_Redrup
(answering for Pete - cheekily) Yes - but it's technically a "rotary" - the crankshaft does not rotate.
an engine mounted in the rear wheel and of rotary type to be clear, Wikipedia have confused matters somewhat. https://en.wikipedia.org/wiki/Millet_motorcycle