Dripple and Eaglit are clearly the two most viable Loomians for this badge (snocub can't do jack squat past the first theatre, fevine gets mauled by everything, vambat and emibt have ineffective movepools and stats, and weevolt doesn't have any advantages over anything).
There are a lot of pros and cons with both of these 'viable' loomians.
With dripple: You can finish the first battle quicker (usually), as it have a higher melee attack stat for it's normal move. Its' stab move (Spray) is less effective against neutral targets than Eaglit's Shine. Duskit is much more dangerous as it can hit with Startle. It can get pinned by any Gekow's Static Shock, but it can use super effective water moves against them too, making is arguably better for Route 3 and the first Theatre. It is very slow and is usually out-sped, however, this is compensated with a better overall defense.
With Eaglit: The first battle will be slower (you in fact have a chance of downright losing). Its' stab move, Shine, is better against neutral targets than Dripple's Spray. Duskit is mostly a cakewalk as Startle has no effect on it (unfortunately Final Ruse WILL kill it if used on it's final turn). It gets walled by Geklow, and many turns have to be wasted on clearing them out, meaning that many potions have to be used on the First Theatre. It is faster and more offensively powerful than Dripple.
So why is the run suddenly harder?
Well, for one the Battle Theatre will be very hard for both loomians (because of the Geklow there), and can end perfectly good runs.
Two, the Antsee and Sludgling trainers are likely to hand status effects to your loomians with Mystery Toxins. While Sleep can be shrugged off with luck, either paralysis or poison will very likely spell the end of your run. Sure, you could ignore both of these trainers, and it is probably the safer option, but doing so could put your Loomian one or even two levels below their normal level, which is not ideal for the First Theatre.
The good news is that, after the Harmony Medal, the run gets a lot easier. Assuming your Dripple or Eaglit isn't severely underleveled.
So which starter is objectively better for the second medal? Or is Snocub still usuable in any way?
This is true, the 2nd gym is really hard to speedrun, I have tried with every starter... but I have not seen good results and with snocub up to route 4-5 is when i died.
I don't personally attempt both gym runs but from your thread it seems like it would be a real pain to do lol. Snocub could have some use when it comes to getting routes done quicker, but I think Eaglit should definitely be incorporated into both gym runs.
We could catch an Earth type loomian and level it up from benching to get the 2nd gym done quickly, I done some research; it seems like we can use an earth type to get the 2nd gym done quicker. But it will waste 5-15 minutes from all the text boxes that it will get from leveling them up from benching them, so how do we level them up quicker then? My suggestion would be to after defeating the gang of 3 people when you use shine, you use the loomian you caught (should be Earth type like what i meantioned earlier) for the rest of the game to level it up. Not a great strategy but Fire is weak to Earth.
The problem is, the earliest Earth type loomian we can get is Babore on route 3. It would take 10-20 minutes to level it up manually and a lot longer when benched. Besides, Geklow makes up about 50% of Eaglit's problems, so if we get through that, it should be a lot easier.
Makes you wonder why it was so overrated after the game's release if it couldn't do anything at that point.
EDIT: Fire is also weak to light, so it's probably not going to be the solution.
