there are seems a lot of article made by some niece and nephew regarding this, but Uncle Lee have an itch to slightly add, "correct" or at least straighten it a bit... or just comment about it.
1. regarding Arlecchino... if niece and nephew remember, Uncle Lee called her "ikemen" (meaning handsome guy) before realizing the character is voiced by a female seiyuu. Well ... Arlecchino or Harlequin, originally is a dude. sooo .... yeah... there's that... another character got genderbender... but that's allright. we got ourselves an ikejo! a handsome lady!
and for the love of Archons.. his title is "Servant" both in original Commedia Della'arte AND Genshin (confirmed by CN and JP). not "Knave"! who came up with that... any EN can confirm the irregular title?
2. Puchinella and Il Dottore is pretty much self explanatory. and Mihoyo keeps the mask accurate... or in Puchinella's case, nose is accurate to the mask.

3. Il Capitano and La Signora is more 2 characters that more or less the same quality. they're the exact match and attracted to each other. and La Signora is the wife of Pantalone AND mistress of Pedrolino (sorta Pierro ... but more dominant) AND a courtesan in the original... and she cheats with Il Capitano quite regularly despite being married to Pantalone.
4. that being said .... Pantalone is technically ... a sugar daddy. LOL!
5. Tartaglia is quite accurate despite lack of stutter in his speech. he is indeed quite a dainty fella and a statesman

6. Who's Innamorati? hmm... She's technically the protagonist of the play. sooo ... is Columbina the antagonist? No no no no... she's more or less the "straight guy" character...... ish...
7. Pierrot is ... sorta "downgraded" version of Pedrolino (First Zanni) whos more melancholic. he and Arlecchino often compete with each other. he's the modern version of what we call "sad clown". well ... he just lost his mistress ... his sadness is understandable.

8. Sandrone is the hardest character to find since the character is basically .... puppets. creepy puppets. it was (or is) used to depict peasants.
9. La Signora .. again, see point 3 above. maybe why she's killed off is to prevent overly complicated plot of love affairs and NTR amongst Fatui??????

Figure References:
- Genshin JP Twitter (@Genshin_7)
- Sand, Maurice (1860), Masques et *******s: Comedie Italliene. Michel Levy Fleres, Paris.
- sipario.it/guide/commedia-dell-arte


