I am hoping to upload a close-up of the flowers of this plant to the site, but wish to make sure it is the Green Poinsettia. The reason I am not quite sure is it is taller than the ones we had growing last year. Maybe about three feet tall.

Also, are the red spots a type of mildew?
Thank you very much.

Yes, it's Euphorbia dentata. The red spots are likely are likely result of a viral infection. It's a pretty common phenomenon in plants.