Only when you make the call very brief and apologize those around you.
When you excuse yourself from the room and talk in another area
When the call concerns those you are meeting with (ie., the call is from the boss)
Between 5 minutes early and the exact meeting time so you don't inconvenience anyone.
30 minutes before the meeting time, so you can get your footing on the meeting space.
No more than 10 minutes late.
Leave a message that's clear, short, and to the point.
Leaving as much information as possible.
Make sure that all parties involved have a relevant stake.
Make sure to check everyone's outlook calendar and check for conflicts.
Plan to provide a handout or access to the information to be discussed.
All of the above.
Stay in your office; your co-workers will understand
Give up the work and join the party; there's time to finish everything later
Make a brief appearance, then return to work
As you would normally on Friday, as the concept of casual Friday is well understood
Appropriate for a business meeting.
A bit nicer than you would normally on Friday, but not in anything special.
You don't give much thought to your dress at all and get dressed quickly and simply.
Wait to answer the email when you have time to answer fully.
Send a short message stating your situation and that you will respond in detail as soon as you can.
Here's an interesting quiz for you.