Emma wouldnt be related to Rumple or Milah. If she was married to Neal, then yes, but she isn’t. Rumple and Milah are only Neals’ parents and Henry’s grandparents and nothing more.
I dont find it weird or ‘creepy’- if they were all blood related then it would be a different story. I don’t really see the big deal here.
But (assuming Neal is Bae), I can’t wait to see Rumples reaction when he finds out that henry is his grandson! This is going to be awkward for everyone.