Hi, if I speak just after he has wished me happy birthday, could I also say,‘You are the first one wishing me happy birthday!’
Also if I am letting him know, he was the first one who wished me happy birthday yesterday, can I say,‘You’re the first one having wished me happy birthday!’
Finally “You are the first one to wish me” sounds like an obligation to me. Can you explain this as well!
Informally it would be acceptable, but ‘to wish’ is far more common than ‘wishing’ in that situation, because you have to assume the rest of the phrase if you use ‘wishing’: You are the first one (who is) wishing me…
That doesn’t work. I would use:
You were the first person who wished me…
It’s not an obligation, regardless of how you might think it sounds to you.