The /streams endpoint should have all the information you need (it also contains a channel object), but it only returns any information for streams that are online. You can check several streams at once by separating them with a comma: https://api.twitch.tv/kraken/streams?channel=joshimuz,torikslv
The returned array only contains those streams that are online, so you would have to request the info you need (display name, profile picture) for the ones not online via a /channels/:channel call. I don’t think you can request several in one call for that, but I might be wrong.