It's funny how all you need is one episode to show that Rossiu/Simon is completely canon.
WARNING: SPOILERS, SPOILERS FOR TIMESKIP and Episodes 17
Why Simon/Rossiu is Completely Canon
[warning: pretty image-heavy]
#1:
WATCH OUT VIRAL, ROSSIU DOESN'T LIKE PERSISTENT GUYS SO NEAR SIMON:
ROSSIU: PUT AN END TO THAT FLIRTING RIGHT AWAY.
Rossiu: You have trespassed on MY - I mean, STATE property. In your HEAD."
Rossiu: "AND YOU WILL BE PUNISHED."
#2: I'LL BE WATCHING YOU
Rossiu is disturbingly good at the I'll be Watching You habit of giving obsessive stalkers a bad, bad name.
This is right after Nia accepts Simon's proposal:
Rossiu's SOMEONE IS HOMING IN ON MY SIMON SENSE IS WORKING REALLY WELL:
Rossiu: Yes. Your @$$ is mine, you're not promising it to anybody else.
#3: Princesses Getting In the Way
Rossiu: Yes, and she'll be showing up in short order.
Rossiu: RIGHT ON TIME.
PLEASE BE NOTING ROSSIU'S DRAMATIC CHANGE IN EXPRESSION.
(the eyebrows say it all!)
#4: AND FINALLY, WHY THIS EPISODE IS NAMED WHAT IT WAS:
Rossiu subtext: I DON'T WANT TO LOSE YOU LIKE YOU LOST KAMINA
SIMON IS LESS THAN RECEPTIVE:
THAT'S WHY THIS EPISODE IS CALLED:
Because Stupid Simon is Stupid.