Hi Robin. Welcome to YT!
First, thank you so much for adopting your Megan! I hope that you'll be able to post some pictures soon.
To your question regarding cargo...this is an
absolute no. Cargo for a small dog, let alone a puppy, is pretty much a death sentence. There is no temperature control and no one to watch over them. Puppies are especially vulnerable. This is even more serious with a baby less than 2 lbs...
If there is no way that you could fly there or you son to fly to you, I would recommend looking into courier flights.