My initial thoughts: The game mode is fun, it's nice to see some of the obscure team comps etc.
It appears you should have plenty of energy to complete the event without needing refreshes if you're efficient.
However, you only get like 120 energy a day which is 8-9 battles, you can easily cycle through 2-3 teams and stamina won't really be an issue. I feel like energy is more of a bottleneck than stamina is to my enjoyment of this mode due to how long you have to wait between battles once you use all your initial energy.