Yeah, while the manga came out first for Strider, both the manga and the video game were planned at the same time, meaning that Strider Hiryu floats around that line similarly, but a bit different in some parts, to Lucario.
Lucario was always planned to be in the video games to begin with, but Lucario would earn the role as one of the movie stars before it's game appearance similar to Lugia. But strictly speaking, Lucario is a video game character first and foremost, even though Lucario in Smash is very much based on the movie version.
This is why Geralt from the Witcher series is more than likely not a possibility. While the Witcher games have gained alot of popularity, Geralt is first and foremost a book/short stories character as the books were made long before the games(13 years) and even longer with the short stories(21 years).
Whereas in Strider's case, he was planned for both the video game and the manga and isn't exactly either a video game character or a manga character first, but more a mixture. That being said, Strider's video game appearances would be more a hit with people than his manga. Strider is in that balanced gray area of being both a video game character and a manga character at his origin where it's non-arguable what Lucario and Geralts' origins are, but because Strider's appearances have mainly stuck only to the games since his creation, Strider Hiryu has that chance of getting in Smash due to him leaning more towards his video game heritage over his manga heritage.
And on the subject of Strider, while I would love to hear what Smash Bros. does for it's St. Petersberg theme, it's going to be hard for Smash Bros. to make a St. Petersburg theme as good as this version.
