I have no specific reason to deny that the spherical area is a reactor (I tend to think so, myself) but I would be careful identifying too many parts based on trying to find corresponding structures on Cloud City, as that is from a totally different franchise in an unrelated universe and served a very different purpose.
I wholeheartedly agree that you shouldn't mix different franchises, but Earth Spacedock was designed and built by ILM which also designed and built many Star Wars
vehicles. Given some obvious resemblances we could wonder whether they successfully "switched" from SW to ST mode.
(A drydock in space doesn't hold much water -