Nope...
This is usually the sign of a network issue (lost packets resulting in out-of-order UDP messages, slow or failing DNS, dropped packets...).
Yes, good example... Packet out of order, meaning network issues...
Not an issue, just being reasonable (this means still 8000 messages per second processed at 20fps... Should be more than enough !).
Yes (the Marketplace listings feature is a per-sim capability), and not an issue either.