Out of curiosity, do you happen to know of any footage of Komodo dragons diving? They're obviously efficient surface swimmers, but I can't find anything more than anecdotal suggesting that they actually go underwater.
Either way, I agree that at least the Nile monitor needs to have diving added still. I'm just not certain it will at this point.
Not sure if there's footage on the internet, but it is cited in literature that they do dive. Zoo specimens also use all parts of their pools in enclosures. However, they are not ecologically as aquatic as some other species like Nile or water monitors, at least when they are adults. Juvenile Komodos have a tough life, mostly because of their own kind regularly hunting them, so they use different adaptations like climbing to escape them. So I can imagine they'd also use diving into murky water as an effective escape behaviour as well, not that adults can't follow them in, but because of poor visibility and loss of direction during a chase.
I agree that at least the Nile monitor needs diving and Komodo can be omitted, but lumped them together since they have similar models and identical animations other than the legs, so thought it could be done at the same time as if they were the same animal's life stages. But I'm not a game developer or animator, so this is just a guess.
This might sound like a weird Suggestion but Proboscis Monkeys do also sometimes dive in real life
I've also read that they do swim underwater for quite some distance actually.
Tapirs also need underwater animations.