If anything them not mentioning Estelle looks sus to me, I think she's popular enough among Falcom characters to be considered. All of this assuming Falcom is getting a character, of course, which is a separate matter. If I was Falcom's president I'd try to avoid to mention the name of the character I know is getting in Smash, even if it's just in case.
About Adol yes, it doesn't make sense. I think he would qualify as a swordfighter. I guess his comment was because of how Ys games usually play and all that, I guess?
Also there's this interview from September 2018, where they asked Kondo, Falcom's president, if they would be okay with Adol in Smash Ultimate, and he basically said they would be delighted. At least, that's what says google translate:
A l'occasion de la sortie sur Nintendo Switch de l'excellent Ys VIII : Lacrimosa of Dana, nous avons posé quelques questions à Toshihiro Kondo, président de Nihon Falcom. Si vous n'êtes pas familier avec la compagnie japonaise, on rappelle qu'ils sont derrière des jeux souvent de niche en...
www.actugaming.net
Then the other interview you're alluding to, which I don't remember when happened (it was last year, I think), Kondo certainly talked about Rean. If I'm not mistaken Rean is his favourite character so there's that. But if Nintendo or Sakurai wanted another character they would get that one, unless Nintendo and Sakurai approached Falcom for a character, no matter who, and then decide which one would get in once they started negotiations with Falcom. But I think this isn't really a likely scenario, I'd guess Sakurai would at least have someone in mind before approaching Falcom.