Dating someone of an equal level to you is allowed. Dating above/below your position within your store is not allowed. Dating someone above/below your position from a different store is allowed.

Who cares? Do what you wanna do!

No idea but it’s not against the code if nobody finds out

It depends. Managers should not date people they manager because it creates conflicts of interest and bad power dynamics. But it's fine for a barista to date another barista.

I’m in Canada so I’m not 100% sure if this applies to the U.S. But there was a partner at my store who was a shift and ended up dating a barista but due to power dynamics that come with the roles the shift had to go back to being a barista. So I guess its not against code between baristas or partners between different stores UNLESS it impacts work relations/ obvious favouritism.