Ok, since I like doing side quests and all that stuff, it's gonna take some time for me to reach farther points of the story, so I'm uploading what I have for now, regarding the ones that I originally missed from the first and second trials:
1st Trial:
019-01 - Rattata - 9894ED4A2BE9 (Wild 1).pk7
019-01 - Rattata - 41F7FBB9C9D6 (Wild 2).pk7
020-01 - Raticate - CC01FDBA5153 (Wild).pk7
734 - Yungoos - 0A758472F501 (Wild 1).pk7
734 - Yungoos - 89E32855D28A (Wild 2).pk7
735 - Gumshoos - D644CCDE822D (Wild).pk7
735-01 - Gumshoos - B3D334C29C3F (Totem).pk7
734 - Yungoos - 31BC765B20AA (Totem's Ally).pk7
I must point out that both wild Rattata/Yungoos (recpectively) are technically identical. I dumped'em as separate Mons just for the sake of completion.
Also, by checking abilities and movesets, Raticate and his underlings seem to be easier than their Yungoos/Gumshoos counterparts (even more than I thought by the typing itself).
2nd Trial:
751 - Dewpider - 070F273AD427 (Wild 1).pk7
746 - Wishiwashi - 4D7FA35CE0C8 (Wild 1).pk7
751 - Dewpider - 4686C2074333 (Wild 2).pk7
746 - Wishiwashi - EC28AF5AC2EE (Wild 2).pk7
Again, both Dewpider and both Wishiwashi are identical, but as I previously said, completion
Also...
Got some more uncatchable Mons in addition to these ones:
019-01 - Rattata - 0B7D85921069.pk7 - First wild encounter in UM, when half the grass path after getting starter has been walked; nature apparently set to Mild, and ability set to Gluttony; just like ambush encounters, seems to ignore repels (though no repels are legitimately obtainable at that point).
734 - Yungoos - C0CC88DE70E7.pk7 - Same as the Rattata above, but exclusive to US and ability set to Stakeout (still ability 1).
021 - Spearow - 1529ECFC1BF4.pk7 - Fought in Plank Bridge before saving Nebby. Has a "special" moveset: regular Lv. 4 Spearow should have Peck, Growl and Leer; this one doesn't have Growl and has got Pursuit instead of Peck, most likely to prevent it from wiping out Rowlet (which not only has type disadvantage but both attacking moves it should have at that point are physical, and therefore hindered by Growl).
Note: The UM-exclusive Rattata and Raticate that I missed before were now dumped by loading my US save from UM at the required points