I would give a list of English names to the students on the first day so that they can pick one. A lot of students like to have English names but some don't. The ones that have English names are easily remembered whereas the others you will have to make more of an effort to remember them. Also calling them Mr. Lee or Mr. Wang is another option.
About ground rules, it depends on your style of teaching and their position in the company.
If they are high level managers then they might miss a lot of classes, which might be dishearting for any teacher.
Student with low English levels might resourt to speaking a lot of their native langauge in class and get another to translate.
Everybody has mobile phones but do you allow them into class? If you do then do you kindly tell the student to take it outside?
Having said all that, you'll find soon enough that adults are very much like kids, they like to play games sometimes, like to joke around and like to interact with their classmates a lot. Just don't let them play too much!
Best of luck,
LiK