144 hours in Shanghai with two different carriers

Hi

We're looking to do this:

1. Fly in to Shanghai from Tokyo with Peach Air
2. 144 hours or less later, fly out to Moscow and on to Amsterdam with Aeroflot

We'd only be able to show a reservation confirmation (non-refundable) for aeroflot to the customs officials upon arrival (as proof we'll be leaving again) as we'd not be able to check in for tickets that early.

Would this work? Is there something we forgot?

Thanks!