Did Ellen White say chocolate is OK?
Mrs. White made no mention of chocolate or cocoa in her writings, so I have nothing to offer you regarding her stand on cocoa. As for the caffeine issue, cocoa does not give people a caffeine “kick” the way coffee and other caffeinated beverages do. So it does not seem to be a stimulating beverage. If there is caffeine in it, it appears to be in amounts too small to have a measurable effect on the body (pulse rate, wakefulness, edginess, etc.). In light of these things, it may be best to leave the matter of the use of cocoa to individuals to decide for themselves.
Regarding UFOs, I know of no statement from Mrs. White that might be taken as applying to them.