If MLP Equestria Girls were to crossover with D&D(considering that Hasbro scrapped their nice Elemental Plane idea for G5 they pretty much owe us) they should take full advantage of Belief Shapes the Planes and have Discord run the tour!
Thalasia(Sailor area with Zero Pirates), Aquallor(Mermaid and Sea Elf Area) and Mercuria(where the Divine Lotus AKA Asian Religious Afterlife with it’s Sea of Milk is found) should be where all the Media References are found with Thalasia being first and Aquallor being last(for the Media Refence locales).
If the HuMane Cast were to visit Thalasia(a Sea-based World of Goodness AKA no pirates) in Elysium one would expect(after learning about Belief Shapes the Planes and seeing the Layers as their own Universes with their own versions of themselves) Pinkie Pie to mention Cloud Kicker(whose Pony counterpart dressed as Sailor Moon during Nightmare Night) wearing an Anime Character’s Sailor Outfit on Halloween only to be reminded that that Sailor Outfit looked more regal than Naval only for Pinkie to rebut that said Anime Character wore a more Naval Sailor Outfit when not in Magical Girl Form.
Of course Pinkie Pie being Pinkie Pie(and having studied the Lore on Cloud Kicker’s Costume because she needs to know everything about every Person in town for the sake of her Parties) will promptly(after someone mentions Copyright Law) mention that the Magical Girl shares a English Voice Actor with a girl with White Eyes(Hinata Hyuga) who shares a Japanese voice actor with 2 Girls with Double Ponytails one of which has Red Eyes(Alicia Testarossa) and has a Clone with the same Voice Actor(Fate Testarossa).
Once Belief Shapes the Planes pulls out a Cloud Kicker that looks like a Usagi Tsukino without Odango and with Cloud Kicker’s Bangs and Eye Color one can imagine Pinkie Pie mentioning how the Magical Girl Cloud Kicker dressed up as is the reincarnation of a Moon Princess whose Mother the Moon Queen shares an EN Voice with an Otaku and a Reality Warper(Konata and Haruhi both of which wear Sailor Suits) and that they share a JP Voice with a Girl with a Nasty Notebook(Misa Amane).
Discord will probably cut in at that point to mention that the Girl with the Nasty Notebook shares an English Voice with Pinkie Pie and Silver Spoon and that Silver Spoon shares a Japanese Voice with Rainbow Dash who shares an English Voice with Applejack.
Since Pinkie acts like the Reality Warper(Haruhi Suzumiya) her Thalasia Counterpart will(because of Belief Shapes the Planes) be a Pinkie Pie Color Scheme version of that Reality Warper while Rainbow Dash who acts closer to Konata Izumi will have her Thalasia Counterpart be a Rainbow Dash Color Scheme version of Konata.
Since Rainbow Dash has the same Eye Color as Cloud Kicker her Thalasia Counterpart will naturally be Cloud Kicker’s Thalasia Counterpart’s Mother from her first Life. Ah! But what about her second life? Since by now Pinkie Pie has mentioned the Double Ponytail wearing Girl who was cloned she will mention how that Girl’s mother shares a Voice Actor with a Sea Witch causing Delays(Witch of Delays from Pretty Cure).
She will also mention the Clone having a Rival who is a Mage of Stars(Nanoha) who shares an English Voice with a Girl in a Red Sailor Suit who uses Fire(Sailor Mars) and a Japanese Voice with a Ninja(Tenten from Naruto) who shares an English Voice with a Girl who dresses like a Bat(Batgirl). Discord would immediately take over and mention how that Girl in another Adaption shares a Voice Actor with Twilight Sparkle.
Discord will also mention Twilight Sparkle how shares a Japanese Voice with a Virtual Reality Player who plays a Cat Girl and a Sun Goddess and when Pinkie can’t fill in any more info due to only studying Cloud Kicker’s Outfit and not knowing the existence of the HuMane Cast’s Voice Actors will go on to mention how the VR Player shares a Voice Actor with both a Moon Kitty(Luna), an Interface(Nagato Yuuki) and a Schoolgirl in a Sailor Suit(Tsukasa Hiiragi from Lucky Star).
Cue Thalasia Twilight Sparkle showing up as a Nanoha who wears Tsukasa’s Summer Uniform with Sailor Mars’ Color Scheme and Bow. Discord will go on to mention how the Schoolgirl in a Sailor Suit has a Big Sister who shares a Drama CD Voice Actor with Sunset Shimmer and an Anime Voice Actor with Fluttershy. Cue Thalasia Sunset Fluttershy Shimmer showing up resembling a Kagami Hiiragi with Fluttershy’s Hair Color and Sunset Shimmer’s Skin & Eye Color.
I’m sure the HuMane cast will have enough curiosity peaked to ask about Rarity. Discord will mention how Rarity shares an English Voice Actor with Principal Luna and a Girl dressed as a Sailor wielding a Fiery Sword(Shana) who shares a voice actor with a classmate of the Mage of Stars also dressed as a Sailor and also wielding a Fiery Sword(Arisa Bunnings). Cue Thalasia Luna Rarity who resembles Arisa Bunnings showing up.
The HuMane cast discovering Luna’s Thalasia Counterpart(who is also Rarity’s Counterpart) will cause them to ask about Celestia’s Counterpart. Discord will mention that she shares a Japanese Voice with the Mother of the Schoolgirl who shares a Voice with Fluttershy and Sunset Shimmer. Said Mother also shares an English Voice with a Girl in a Sailor Outfit(Ayano Minigishi). Cue Thalasia Celestia appearing and resembling(and sharing a Voice with) Ayano Minigishi with Celestia’s Coloration.
Trixie Lulamoon being a Narcissist will demand to have her Sailor Outfit-wearing Thalasia Counterpart revealed which will result in Discord mentioning that Trixie shares a JP Voice with a Guardian Knight(Shamal) of the Sailor Outfit-wearing(in Civilian Form in the Movie Versions) King of the Night Sky(Hayate Yagami) who she shares an EN Voice with alongside a Schoolgirl who shares a JP Voice with a Girl in a Sailor Outfit who gets Migraines and Chest Pain when feeling lonely(Michal Amagi).
Cue Thalasia Trixie Lulamoon showing up as a Trixie Color Scheme Hayate Yagami wearing Michal Amagi’s Sailor Outfit and suffering from Migraines and Chest Pain when feeling lonely thus making her very clingy(as if Hayate wasn’t already more blatantly clingy in Lyrical Nanoha Innocent than Michal from Mermaid Melody Pichi Pichi Pitch! was) while acting much cuter than Canterlot High’s Trixie.
Discord will point out Starlight Glimmer who is believed(Belief not Facts shapes the Planes) to share a Voice with a Mermaid(Seira from Mermaid Melody) who can transform into a Girl who wears you guessed it: A Sailor Outfit. Incidentally he will mention that her Hair while Shoulder Length while in Human Form in one Episode her Hair is as long as her Mermaid form’s due to using a Wish.
Cue Thalasia Starlight Glimmer showing up as a Starlight Glimmer Color Scheme version of Seira and wasting a wish on a wishing rock for Hair reaching down to her knees like her Mermaid form has.
Yes. Thalasia is the best place to reference Sailor Outfit wearers who have even the slightest connection to MLP Cast.
Mercuria will be the best place to reference Miko(Twilight as Rei Hino’s Miko persona and Tsukasa’s Miko Persona combined & Fluttershy Sunset Shimmer as Kagami Hiiragi’s Miko Persona), Youkai Hunters(Starlight Glimmer dressed as Sango who she shares an EN Voice with) and Ninja(Trixie as Ino Yamanaka who she shares a JP Voice with).
Aquallor will be the best place to reference Sea Elves(Fluttershy and Pinkie Combined into AndrAIa from ReBoot) and Mermaids(Twilight Sparkle as Melody from Little Mermaid 2, Starlight Glimmer as Merliah from Barbie in A Mermaid Tale, Celestia as Queen Calissa from the same film, Queen Chrysalis as Eris from the same film, Trixie Lulamoon as Dot from ReBoot during the Mermaid game Treasure of Atlantis that AndrAIa comes from).
Those 3 Layers of Specific Planes so easily lend to Media References unlike the other Layers and Planes that once done the Show can get creative making the Mane Cast’s counterparts match the Aesthetics of each Layer of each Plane(Paladins for Lunia, Pirates for the Surface of the Plane of Water, Swamp Natives for Belierin, Elves for Arvandor, Vikings & Valkyries for Ysgard, Demons for the Abyss and the Mean Six for Agathys in Tartarus to give examples).
The Nine Hells, Pandemonium, Gehenna and Limbo will be Off Limits due to their names. We are already pushing it with Tartarus(appeared in MLP), Hades, Acheron and the Abyss as it is!