As a Wahoo, I probably shouldn’t be responding, but I’ll try my best at answering some of your questions

1) DL will generally not be able to check your bags all the way through because it’s not on the same PNR. You might be able to get an agent to help you, but it’s complicated because your itinerary involves MU on a separate ticket. I imagine that your bags will probably need to be weighed and processed by MU agents at the check-in desk. Then again, you might find an agent who can really do some magic — I’ve had this happen in the past. A lot will depend on how much energy the DL agent will want to put into this...

2) I’m 99.9999% sure that DL won’t be able to print off your BP for an MU ticket. They’ll likely refer you to the transit desk or possibly the check-in desk for this because your flight officially originates in PVG.

3) You can try to get your BP online via the MU site or app, though, TBH, both are really buggy. I was unable to check in for my flight online from CEB.

4) I just got back from this trip to CEB, and it was hectic because of my delayed flight from CEB to PVG. Not only did we sit on the tarmac for 15 minutes at PVG after a 3 hour delay, we parked at a remote stand close to where the new terminal is being constructed — it was far away. Then, we had to be bussed all the way to immigration/customs. From there, I had to re-clear security and then get my passport scanned. The lines, even for J pax, were messy. I didn’t check luggage, and if you plan on checking luggage on a separate ticket, I imagine that you’ll likely need to pick up your bags and then re-check them at the check-in desk.

Good luck!