How much till the swap is discovered?

I think everyone knows, just pretending for her because she's not opening up yet since they have a contract. ╮(￣▽￣)╭

Going by typical manga logic there is that option or the option of nobody knows even if it's super obvious and easy to investigate

Everyone already knows, girl can NOT keep a secret lol. She is just too much of an airhead to notice, it’s great

Then how much till the secret about everyone knowing gets out?

Good question but probably not till the end given the peak of the future we saw in the beginning