Question from Pendragon525 - Lady in waiting to all of Henry's wives

I attended a lecture on Tudor-era women in England, and the lecturer mentioned--briefly--that there was one lady-in-waiting who served all 6 of Henry VIII's wives. Her name was not given. I have researched this with no success. Does anyone know if this is factual, and if so, who the lady in question was?

I brought this up to a fellow history buff who thought that the lecturer might be referring to Jane the Fool, but I can find no evidence of Jane in Katherine of Aragon's service, and she looks quite young in the famous "family portrait" painting; she appears to be of roughly the same age as Mary I.

Which brings me to my second question: why were the fools in that portrait at all, and was that commonplace? Are there other such paintings?