Biggest threats:
Team 1
Zamazenta: IDBP rolls over Team 2 if Venusaur is down or even if Sun can't go up again, which can be easy to force. It also threatens out Corviknight, which is a huge plus. It could also be the AoA set, which allows it to deal massive damage to everything barring Torkoal, which hates being chipped anyways. Overall, I'd say Zamazenta is one of, if not the, biggest threats here. The main way to deal with Zama would probably be by chipping it down with Venusaur in Sun and finishing it off with Raging Bolt, but that's harder said than done and it can run away with the game or break the door down for Scarf Lele to win the endgame.
Tapu Lele: Quite a lot of you latched onto the idea that Tapu Lele was the biggest scare to the opponent and I can see why. My thinking here is that Corviknight is very overloaded with defensive duties here, as it has to Defog so that Torkoal doesn't die and come in to answer Mega Venusaur, Landorus-T (which both can Knock Off Corv's HDB, meaning it takes Stealth Rock damage as it comes in repeatedly), and Tapu Lele. I think this composition looks like Scarf Lele and some other Hisuian Samurott set (probably Black Glasses 3A), considering that this team has a robust defensive backbone that aims to wear down Steel-types for Scarf Lele rather than flat-out rip through them (although Heatran does just that). Corviknight is fine here, but it struggles to take on all 3 things it wants to while Defogging without its Boots.
Team 2
Venusaur: Team 1 horribly struggles to switch into Venusaur, with a Heatran that I could easily see being offensive and a Lando that gets flat-out 2HKOed by Weather Ball in Sun. However, Mega Venusaur is actually a surprisingly decent counter, with Weather Ball only having a 0.4% chance to 2HKO and Sludge Bomb from Mega Venusaur having a 88.4% to do so in return. Additionally, 75% Synthesis allows Mega Venusaur to mow through sun turns and neutralize the biggest threat. Unfortunately, if it sets up a Growth, it becomes a game of sacrifices, but it can't go for a Growth on Mega Venusaur or Heatran considering a +2 Weather Ball in Sun just barely misses out on a OHKO and Sludge Bomb 2HKOs back most of the time while Magma Storm evaporates Venusaur. The only real Growth target is Lando-T. This is handicapped by Sun though.
Raging Bolt: Mega Venusaur is actually a rather capable answer to the standard CM set, never being OHKOed by Proto-boosted Draco while 2HKOing back with EP. Unfortunately, Dragonium Z decimates Mega Venu and the rest of the team is pretty weak to it, meaning it's overall a larger threat on the team. This does, however, become a massive issue if Tapu Lele comes in and blocks Thunderclap.
Overall, I'd say Team 1 has the advantage here. Growth Venusaur and Raging Bolt are impossible to stop over the long run, true - however, the fact that Scarf Tapu Lele and Zamazenta (or Specs, as some suggested) completely steamroll the opposing team by forcing chip damage on their common answers while being able to be brought in by safe pivots means that Team 1 likely has the advantage here. This is a puzzle that I'd say has no definitive answer on team preview and answers went both ways; however, the crux for me is that correct prediction (or Air Balloon offensive Heatran) makes it hell for Torkoal to set sun up and to get into Venusaur without taking major chip damage or sacrificing something else to force this progress. Additionally, Team 1 does have limited-time checks and things it can burn in order to make dealing with the two biggest threats in Venusaur and Raging Bolt, while Team 2 really doesn't have much besides Mega Diancie and Great Tusk before it starts sacrificing things it really needs for its gameplan. Additionally, Corviknight being the only safe pivot opens up a whole host of opportunities for Heatran to come in and throw off attacks, and considering it's a major threat, that is not what Team 2 wants to allow to happen. Overall, if both players play just as well as one another, Team 1 should win, but there is certainly room for an outplay.
