Would Chromecast work?

it can work. you just need the right methods. 

Here, try this:
1. Connect your webe connection to your computer. (don't care how you do it, just make sure your PC is using the webe connection) 
2. Make sure your Chromecast and your PC are within the same LAN
3. Make sure you have installed the latest Chrome browser version and use the built-in Cast option
4. Use any media streaming service you want to cast it to your Chromecast. I've tested iFlix, Twitch and AnimeFTW.

Note that Youtube and Viki don't seem to work as it forces your Chromecast to connect to the streaming servers directly. I'm guessing that services with full fledged Android TV apps will behave similarly. Enjoy! 

no special tricks here. no hotspot or VPN is needed. 

it's just how the casting feature on Chrome browser works. You can cast local content from your PC to the Chromecast too. It's the same idea. Basically, casting through Chrome browser will use the internet connection from the PC. So, if you're using the webe connection on the PC, it's one-to-one.

Do note that certain services work differently like Youtube and Viki.