Technically, we did take a bit of a risk with choosing the super hostile Espurr rather than Rattatta, Shuppet or Nothing.
Really? That's funny, because I would label Espurr as the safest possible option the thread could have been given at the time.
It's a third badge Pokémon with a wide variety of moves, including one of every type. It can talk to Mary directly.
Yeah, it eats up a load of AP to get it useable; but Shuppet would have eaten up a load of AP being trained, Rattata would have needed bonding and training to get as versatile a move set and equivalent power, etc.
The risky option there would have been choosing to take no Pokémon and banking on getting an even better option later on, or pinning all your hopes on Dreepy directly and hyper focusing his training.
But let's take a step back, yeah?
See, what did Nemona demonstrate during her battles?
Her Chimchar demonstrated a mastered move. It demonstrated knowing multiple kinds of moves. Most directly, it also demonstrated, you know, evolution; it's now a Monferno.
Nemona started off better at battling than Mary, with a stronger Pokémon, and every appearance of hers in the quest shows her fixating further on battles. She's getting stronger faster than Mary is, and she's not afraid to take on battles she'll lose to get stronger faster.
If Nemona doesn't have three badges by the end of the second field exercise, I'll eat my hat.
If the thread wants this to be an actual rivalry, they're going to need to stop being scared of downsides and start actually shooting for options to gain strength even at cost to Mary. Otherwise, that sun is going to set, and Mary will be left behind.