The web client tries to optimise the user experience by trying to get all information as fast as possible. It then helps to open multiple TCP connections to get at the various resources that make up a web page, e.g., the text content and graphics.
tcp.analysis is the Wireshark analysis of the TCP sequence numbers and acknowledgements so far. It includes metrics like RTT, bytes in flight, bytes since last PSH. The flags are noticeable aspects of the current packet.
Yes, add a column (type custom) with field tcp.stream as field, and use that to sort.
