@Background Pony #CD53
Also G5 movie Japanese dubs

私 (watashi) = Sunny, Phyllis, Pipp, Queen Haven
あたし (atashi) = Izzy, Zipp
僕 (boku) = Hitch, Sprout (as a kid or to his mother)
俺 (ore) = Alphabittle, Sprout (as an adult who’s not his mom)

@Background Pony #CD53
Impressive, very nice!

Japanese Dub self pronouns from what I’ve heard so far…
Mostly Season 1-4 and Movie dubs are avaliable :

私 (watashi) = Twilight, Fluttershy, Rarity, Celestia, Cadance, Maud, Diamond Tiara, Apple Bloom, Sweetie Belle,Trixie, Cheerilee, Little Strongheart, Caleano, Tempest
あたし (atashi) = Pinkie, Applejack, Granny Smith, Babs Seed, Gilda
我 (ware) = Luna
僕 (boku) = Rainbow Dash, Scootaloo, Spike, Shining Armor
俺 (ore) = Discord, Snails, Garble, Cranky Donkey, Capper, Storm King
わし (washi) = Chief Thunderhoof, Steven Magnet

Damn, Big Mac said too few to the point I cannot catch his pronoun!
(Some other characters may said too few lines as well)
Characters in Japanese dub also actually rarely uses self pronouns, but once you hear, it is fun to know.

Ps: Rainbow Dash and Scootaloo are Bokukko, rare females those uses “boku”. Gilda and Babs Seed are weird ones.
Pss: “watashi” is the most used one in here due to high amount of female casts, contrary to shounen anime that often uses “ore” more.

Thanks to this subreddit : https://www.reddit.com/r/mylittlepony/comments/ho5y4c/does_anyone_know_were_i_can_watch_a_japanese_dub/
And this : https://tvtropes.org/pmwiki/pmwiki.php/UsefulNotes/JapanesePronouns

Also facts: https://www.wa-pedia.com/language/japanese_personal_pronouns.shtml

If Season 5-9 and recent specials really got Japanese Dubs (and more to perfectize), there are pronouns I guess they think they’ll use for each, but so hard to guess I think.

私 (watashi) probably used by Zecora, Silver Spoon, Coco Pommel, Marble Pie, Octavia, Bon Bon, Derpy, Silversteam, Ocellus, Meadowbrook, Cozy, Luster, Sunburst, Sandbar
あたし (atashi) probably used by Yona, Somnambula, Limestone Pie, Lyra
我 (ware) probably used by Chrysalis, Starlight Glimmer, Mistmane, Neighsay
僕 (boku) probably used by Smolder, Ember, Daring Do, Spitfire, Soarin, Big Mac, Button Mash, Braeburn, Stygian, Thorax, Dr.Whooves, Cheese Sandwich, Sans Smirk
俺 (ore) probably used by Gallus, Snips, Rumble, Seabreeze, Thunderlane, RockHoof, Bulk, Flash Magnus, Pharynx, Ahuizotl, Caballeron, Sombra, Tirek, Grogar
わし (washi) probably used by Dragon Lord Torch, Starswirl

Pss: More “ore” and “boku” usage in my guessing?? Season 5-9 introduces more male casts and more lines to them, not to mention the movie itself that already got Japanese dub. While Sunburst and Sandbar are probably the rare males using “watashi” because they are really soft-speaking males. Smolder, Ember, Daring Do, Spitfire are probably gonna be Bokukkos.
Psss: Before I heard Fluttershy’s Japanese Dub, I expected her to use “atashi” because it adds cuteness to the sound, but she’s still has a cute voice in “watashi” anyway :3
Pssss: When will G5 Japanese Dub is out??

Japanshy compilation
 
Japanshy while Twilight and Spike are in English

Didn’t know I could get braces flashbacks

Ohayo Flutterchan!