Ah, sorry, I see now, but the underlying point is the same. You should not reveal any information. A "We have sent an email to the address associated with the account" would be sufficient.
The amount of disclosed information, and it's utility, is non-zero, but simply weighs less than the amount of damage from not hinting which account to check.
Accounts can grow to be 20 years old and even a "normal" person who is not actively using lots of addresses for security, will still end up having used several in the fullness of time and completely forgotten about some, yet, may still have or can regain access to them if only they knew to go look.
You don't see how that can happen or really be a problem? Oh well, consider yourself informed that it does happen and is a problem.
Not if you have multiple email accounts. Many times these codes reset in just a few minutes, you should try to avoid forcing users to spend time logging into every single email they can remember just to wait for an email to pop into one of them. You can show a few characters of an email or the first character of the domain to give a lot of info out in relative safety.
Everything is about tradeoffs, and the only objectively wrong answer is this dogmatic "never do $X" nonsense.