I think Kingambit would be a lot harder to handle without Zamazenta and Ogerpon-Wellspring, with the latter almost certainly being banned in the next suspect test if Zama were banned. Ogerpon-Cornerstone and base Ogerpon are nowhere near as splashable, and a lot of the lower-viability mons you listed as answers are just not great in general. While I could see Kingambit being managable with Zama gone, it will be a lot harder to deal with if Wellspring also goes.
I don't know if this is true in regards to grasspon; Grasspon's difference with waterpon isn't in splashability, as I'd argue grasspon fits on a lot of teams that waterpon can't fit on thanks to its tera and being able to run boots.
As well, I've been going over my thoughts on the metagame in regards to potential next steps. I've lightened a bit on Waterpon, although its still largely deserving of a suspect in my opinion. It's power and speed within the metagame is really centralising, to the point where balance is largely forced to build around it in terms of the offensive mons it can fit on it. 110 speed should be very fast, but because Waterpon is so strong it actually becomes rather mediocre; offensive mons that don't have 110 speed become much worse because of that. As well, Ivy Cudgel being an earthquake with a crit chance can become really annoying. However, balance has started to find ways of playing against it that are already quite solid. Grasspon, Zamazenta and Dragapult are all great offensive mons that can often come in on Waterpon while still providing a ton of value otherwise. It also is legitimately hazard weak, so despite its general silliness there's an argument to be made that, while the meta has centralised around it, its done so where its not a problem.
However, I think Kyurem is actually potentially more suspect worthy then I initially thought. Kyurem is weird because despite its sheer power, I'd argue its awkward to build around on balance, where its awkward speed tier and defensive typing means its often too poor into offense. Boots Kyurem I'd also argue is kind of an awkward set with the sheer amount of Gking everywhere. What I'd argue breaks Kyurem is specs; theoretically, specs should be okay. You can build around it through freeze dry resists and protect spam cores, and Gking can theoretically scout it and then move to a freeze dry resist. As well, building with waters means that Kyurem can often be forced to click the weaker freeze dry instead of ice beam. However, I think this skips the big issue with Kyurem which is its freeze chances. Kyurem can often just get away with clicking ice moves repeatedly and fishing for the freeze chance on all its moves, especially with specs, where it can hit so hard with tera ice that it often doesnt even need to predict, unlike with boots. This means that every time a freeze dry resist comes in, its not only taking massive damage but its threatening to get frozen, something that can outright cause a loss, or at the very least move the game state to a near irreversible point. This is especially true considering that often both boots and specs Kyurem run 3 ice moves, meaning its even more dangerous. If Kyurem can click 4 ice type moves in a game, this means that it has a roughly 34% chance to freeze something, which is fairly huge and can actually just lead to kyurem's fishing for a win. Now, Kyurem definitely has problems; specs needs hazard support, and boots often can feel like it struggles against common walls like GKing and Garg. However, I think that the freeze chance as well as the sheer power specs provides makes the trades worth it. As well, the hazards argument I think falls short; Kyurem doesnt need to come in that frequently to have a significant chance of landing a freeze, as well as the fact that you may not be able to get hazards up against it depending on how the match goes before hand. Because of this, I'd argue that Kyurem is really a mon that should be looked at for the next suspect test.