Ilina's existence is canon...
Selenic Shadow was just to make sure Cibryll's skills did not rust (I worked on the majority of it, but had her do things as well)...
Though now, both our skills are rusting away...
Shinica would be playable in Selenic Shadow, but since we made it all up as we went along, it is hard to say for certain...
The LSM trilogy have their own protagonists already...
Original Ilina, original Ilina... how original are you to be playable...?
(The best she currently has is being cosplayed by Kyaro in Apocalyptic Shadow... and the Umbrageous Light version of Ilina...)
I never said her existence wasn't canon, I just said that her appearance in game didn't have to be canon. Ilina being a costume in Apocalyptic Shadow fits that description whereas Data Ilina would probably be a different character altogether depending on how UL plays out.
Also it's funny that Selenic Shadow was created to test Cibryll's modding skills because that's how Gun started out. Regarding SeSh, I figured it was a dying dream world of sorts considering Selena Daria's dialogue, Grie'dyr: Thunder resembling one of the areas in Myst Zone and several of the NPCs appearing there.
It's possible that Shinica may've been playable considering she has a full sprite sheet like Selena and Shinica but also has an alternate costume. Not sure how she would've factored into the story though considering Selena dies and Shinica's story is currently unknown.