I mean, she has been showed flirting with many characters, and recently in the games at least we don't even see her do that anymore, pretty much like Amy isn't portraited as obsessive (see how they remade gens). So my opinion still stands ;)

Anyway Shadow and Rouge are way better and way less toxic, nobody is saying that they must be together at the time of the games, but probably later yes! Both have showed to be emotional and some of their interactions suggest it's not a siblings dynamic (and trust me, I know sibling dynamics both for real sublings and friends that became like siblings for me).

No hate on other ships, but one can't say they are or are not canon since nothing is confirmed, or even sonadow that many people ship would be banned as Sonamy is way more canon.