I turned my streaming stick into a dumb app launcher, and that's all it should be
(www.xda-developers.com)
Chromecast doesnt use your phone for decoding. It just tells the stick to play the video, and it plays it directly. It shouldn't drain your phone at all.
The remote is a personal preference, but I was happy for the phone to be the remote. Having a second remote didnt gain me anything.