1. Half and half/ B. casual and suit??
If your boss from U.K or Middle East, probably suit
2. email both boss your travel plan before you go, if anything changes during trip, you can make call if that is import
You can give your boss daily job summary by email, your boss can check it whenever he has time, also you may be nervous when talked w your boss on the phone
3. You can google western table manner,----OBSERVE ist when you eat with them
4. Good time to socialize w them, go if you are invited
5. research!!!!!!! Don't say if you don't know, relax and confident
Hopefully this will help, just my personal opinion
Sorry cannot type Chinese on my phone