I guess as the Shiori Fujisaki guy, I should address this.
While it is true that most characters in visual novels are not conventional fighters, that doesn't mean they would transform into boring movesets that do little more than superficially reference the original game. Villager, Isabelle, Duck Hunt, R.O.B, and Wii Fit Trainer all take characters from non-violent source material and make them into some of the most unique fighters on the roster, without having a moveset that was designed by a memberberry. A character doesn't need to have every move be a reference to their source material to be a strong character, they simply have to have some sort of thematic glue holding the moveset together. If that glue is "Lawyer who fights by tripping over himself and essentially getting lucky in the middle of the battle until he can get enough clues to yell at the opponent with energy beams" and all moves in the set follow this idea, then I think that's a successful adaptation.
Likewise, I do believe you could translate the gameplay of a visual novel to a platform fighter. Yes, there's really no way to simulate reading large amounts of text in a platform fighter. However, saying a visual novel character can't work because you can't translate this specific mechanic of their genre is analogous to saying a JRPG character can't work because you can't translate turn-based combat directly to Smash or saying a traditional fighting game character can't work because there's no way to translate traditionally blocking directly to Smash. Even if you can't get every 1-to-1 mechanic from the genre working in Smash, you can work within the character's moveset to translate the general feeling of playing their source material.
Using Shiori Fujisaki as an example, I agree there's no way to accurately translate the dating portions of Tokimemo (when you go to the zoo and answer questions about whether or not you liked the Street Fighter movie and all that). However, that's only one mechanic that makes up Tokimemo's gameplay. As such, you could instead focus on building up a character's stats, similar to how you have to have certain stat requirements to meet girls and get their endings. As such, Shiori could be a very weak character statistically, with her specials permanently boosting stats for a stock and servings as keep-away tools to ensure she can get off these buffs. As such, Shiori's general gameplay would mostly be based around playing keep-away and spacing yourself in such a way that you can buff yourself until your stats are strong enough to fight directly. This matches the general gameplay of Tokimeki Memorial, where the challenge is managing your limited time and resources to ensure that both your character's stats and the girl's affection are high enough to get the particular ending.
I can't speak too much on Phoenix Wright and Professor Layton, seeing how I've only played the former series. However, I'm sure there's supporters in the thread who could better explain how the gameplay of those games could translate to Smash.