Twitch is good, but you have to make your own Twitch channel. Best is to ask the kids to set it up and install the app on your phone. Once the app is on the phone all you do is go live. Then have the people in the lot put it on the tv.
The quality of the feed is contingent on the strength of the bandwidth your phone receives. If you check or use your phone in hockey rinks, you already know your phones data service is crummy at best. The rinks who have open guest wiFi typically provide the least available bandwidth they can in order to serve the most on their own network. The typical resolution of a feed is 320p which is good for phone viewing but when blown up on a tv it's going to be pixelated.
My Twitch channel has a variety of tests done with both the rink wiFi and my own dataplan on both a Samsung S8 and iPad streaming to Twitch. I also tried a Google Pixel and the Twitch app didn't work on it. It appears some of the test videos have been stripped off by Twitch because it's been over 14 days, (archives only last for 14 days). The only test that's left is the second test with Samsung S8 and my own data service.Twitch