I fly Shanghai quite often and can confirm your miles will post and it's actually posted like China Eastern on Delta ledger but with the FM flight number.

That said, the BIGGEST problem is they DO NOT follow SkyTeam Elite luggage policies, which could be a nightmare.

1) If you fly out of the US on Delta and connect to a Shanghai flight, you may have to pay for the 3rd piece.
2) If fly out of the US and you overweight your luggage, i.e., >50lbs, Shanghai will make you split your luggage or charge you for the extra weight.
3) Same for return to the US if your first segment is on Shanghai.. It's absolutely 50lbs 2 pieces no matter what level of elite you are.

I fought this battle multiple times and receive written email from customer service leadership that they do not extend SkyTeam Elite luggage allowance and do not extend Delta's elite extra allowance even if you are on a Delta 006 coded ticket.