I don’t know your country/state very well, but the fact that people are going to the opera in jeans tells me, that you might be at a risk to overdress. Based upon “1 kilt 10 looks” I would say that #7-#8 would make it.

I think the kilt – I have one in the American Heritage tartan, too – is fine. And so are kilt hose, shoes and your Argyle. I would go for a standard dress shirt, myself, but I guess the button-down collar should not be that much out of place.

I do have more reservations to your "red" To my opinion bright red shouldn’t go well with the maroon color of your kilt. Accordingly your red should be maroon – to my taste. I would prefer a tie over a bow.

What would you be wearing, if you didn't have a kilt?