I'm not going to give an in-depth analysis, because I'm not part of the team for that and Idc what they say, but take or leave muh thoughts, I give them only to help <3
Theme: I personally love Vocaloids, but I do not think they should be "When flipped face-up" deck, because they are meant to shine! Think of Trickstars, but do something unique.
Art: Where did you find them??? But besides how good the art is, the words on the card are a little off. What do you use, maybe you should ask a person in the discord for help.
Balance: Try to avoid Special Summons from deck with an easy plus effect chain(Like activate any V- Card, NS meiko, SS Luka, Luka Eff to SS Miku, Miku turns your opponent's monsters FD and inflicts damage, then you use Meiko's Effect to flip Luka and add 1 to hand) From 2 cards, you've gained 3 cards(1 to hand others to field) all from your Main Deck without Extra Deck help.
The V- Field Spell does not do much, you have some effects that do not do much, despite it doing good, a field spell that only doesn't give value to the archeteype is something that isn't good. Don't get me wrong, it is an alright effect, but you should reach for some uniqueness besides the gain ATK and give protection effect.
Also, Discarding to add is alright since it is OPT and can be recycled with your other cards, but you should rethink these cards all together.
All of these are opinions: Disclaimer
Have fun in your card making, make sure to ask for help!