Mazel tov! How lovely for you!

I am now going to be exceedingly unhelpful. Maybe.

You say you want a tweed jacket for the day? For the ceremony? Well, either way, I am going to contradict absolutely everyone here, who has given you excellent advice as far as matching a tweed to your kilt goes, & tell you that your instincts for color that goes well with your coloring are right on the money. Whatever you do, do not ever get brown as a neutral. You have strong coloring and should only wear cool neutrals - brown is too warm - unless you get a very dark, "cold" brown (It's hard to explain what I mean. Coffee is a pretty good example of that sort of brown. So is 70% cacao chocolate). The other gentlemen are correct about what looks good in general with kilts, and you won't look badly dressed, and you'll always be able to pair your jacket with other kilts, BUT, if you want with that beautiful dark blue, I think it will look not only very well with both tartans you show, but with go beautifully your coloring.

I apologize for probably throwing a monkey wrench into an otherwise smooth-sailing thread, but I used to color-match fabric & people as part of my job, & just couldn't let this one go by.

Again, congratulations on your engagement, and I wish you a long and happy life together.