1.It'll be an amazing opportunity
2.won't it?
3.I'm
4.Emma's
Here's the modified email body with four apostrophes added as requested:
So, tell me all about this new job! It'll be an amazing opportunity, won't it? I'm so happy for you. Working abroad will be such a fab experience! I also didn't remember to tell you before, but Emma's expecting again, too! A celebration get-together is definitely required!
In this revised version, the apostrophes have been added to "It'll," "won't," "I'm," and "Emma's."