Some things I noticed while playing online last night:
- You cannot receive inbox messages while in a quest, and the only way you can talk to someone not in your group during a quest is if they join your lobby and you have lobby chat turned on.
- You cannot send inbox messages to someone who is offline.
- You can search for people by typing in their ID or name. But, when you search for people, you only can search for people that are currently online.
- There is no "Add Friends" option. The only way you can add friends is to send them a friends request inbox message, and that means you can only add your friends that are currently online.
- Only friends who have Wii Speak can hear you through Wii Speak.
- In-game chat-box is extremely slow and awkward to use.
- Chat log is the easiest way of communicating, so I recommend getting a keyboard.
- I noticed zero lag while playing online last night.
- You can back out of an online quest at anytime.
- I believe you could join a lobby with three other friends, and each one could go on a separate quest but still be able to communicate with each other as long as you are on each others friend's list and have Wii Speak and/or a keyboard (unless you want to stop, bring up a text box, and have a monster kill you while you slowly type "hello")
- Wii Speak is a mixed bag. Some people I can hear almost perfectly and can have a coherent conversation with, while others I have no idea what they are saying.
I'll edit in others tidbits as they come to me. Hope that helped answer some of your guy's questions.