API.Friends.Client.RequestUserInformation(user, getNameOnly)
. You should avoid doing this if possible, in most cases there is no reason to get a user's information for a user that the local user does not "know".API.User.Client.Id
API.Friends.Client.GetFriendGamePlayed(user.cSteamId, out results)
. This returns rather or not the user is in a game and if so the results will be populated with information about that game.API.Friends.Client.GetFriendAvatar(user.cSteamId)
. This starts the process of loading the avatar image from Steam cashe if its not already loaded into memory.