Is this the same canon that had the giant force-eating hamster, Boba Fett blasting his way out of the Rancor, Leia stronger than Luke in the force and a moon flattening Chewie?
"Anything not in the current version of the films is irrelevant to Film only continuity." so you can keep your "canon" in your pants, as it has no bearing on the conversation at hand.
Except Lucas expressly granted EU canon (when he forbade them from going into Ep 1 territory until it was done, he acknowledged that people believed in EU as part of the story) and has frequently taken things from the EU, and the Thrawn trilogy is widely regarded to be the real sequels to Star Wars by pretty much everyone.
Also, Ysalamiri are average sized lizards, not hamsters, Fett got out of a Sarlacc, not a Rancor, neither Luke nor Leia were ever established to be stronger or weaker as far as I know, and Chewabacca was killed by the collapse of a moon into a planet, and never expressly "moon flattened", and for someone who thinks EU has no bearing, you sure do seem to know a lot of trivia about it.
Guess what? It is just as possible as Star Wars to be in Soul Calibur because you have to "extend the universe" (What?! What possible thing could have done this?!) to accomodate it, just like you extended the Spawn universe to accomodate Soul Calibur, using what details you have left. We know from Ep II Star Wars has clones, so, hey! Check it out! I just came up with an in-film canonical explanation for Yoda and Vader! Whoah!

Also,
no one anywhere should care! Jesus Christ! Soul Cailbur doesn't have a fantastic story that you need to gripe about a tie-in, ever! It isn't fucking "Citizen Kane II: Featuring the Terminator"!!