re:
If android or IOS, possibly.
Can't you sideload android apps to Chromecast?
That's not the problem. The problem is being able to WATCH ON A LAPTOP - not chromecast to a TV. The whole point is to be able to watch recorded material, on a reasonable sized screen, when in a location where a TV is not available.
As a side comment - it does not seem possible to use any of the Android screen mirroring applications (e.g. Samsung Sidesync, Mirroring360) with the FIOS Mobile app. You can mirror the FIOS app perfectly, to a Mac - UNTIL you try to play video - at which point the stream cuts out. A couple of vendors have bold me that it's because the FIOS app applies DRM to the stream.