I think that the Kensington Palace PR decisions are based on William's aversion to releasing private information, which I expect is a reaction to the War of the Waleses he had to live through. It looks strange because we are used to celebrities showing us every scar and putting photos from hospital beds on social media. But the senior royals are not celebrities and they don't play by those rules. KP are I think still playing by old royal rules, (Charles seems to be altering these to some extent) and time will tell if they change in the future, after all we didn't know anything much about the late Queen when she was ill
Social media, fuelled by conspiracy theories, is free to fill the vacuum with speculation but it doesn't make it true. The simplest explanation is usually correct and in this case I see no reason why it should be doubted: she had surgery, she is recovering, she'll be back to work after Easter.
I wouldn't be at all surprised if they release a statement once she is well and back to work but equally I see no reason why she should have to release private medical details if she doesn't want to.
As to Andrew, I do love seeing his arrogant, entitled face at family occasions. Every time he is opportunistic and grabs centre stage he is moving himself further away from ever taking a public role again. If he truly believes he has a way back he is delusional and it couldn't happen to a 'nicer' person.