If you're into Japanese food, I suggest you pre-order the Japanese meal by using the web site or calling DL directly. Note that the quality is much better ex-NRT.

Assuming you're new to business class, you'll have access to the SkyClubs in DTW, NRT, and MNL. The DTW and NRT SkyClubs have showers.

I suggest you bring PJs to change into when you go to sleep on the plane. Don't be paranoid. It's practical and shows that you're a seasoned business class traveler. A lot of first class passenger on non-US airlines provide PJs.

On the NRT-MNL flight, you can the flight attendant to leave the food tray on the side of your seat if you're sleeping. I usually fall asleep on the intra-Asia flights ex-NRT right after take-off. And yes, I actually change to my PJs before the flight takes off.

In MNL, there's a carousel where SkyPriority-tagged bags are unloaded.

Will this be the first time you're flying to MNL? If so, I'll give you some warnings about the airport.