I would go with the tweed jacket and whatever shirt and tie you like with the kilt that you wear. I would not hesitate to wear the MacRae red modern tartan kilt to a funeral, and I would not be afraid of a shirt and tie with a bit of color rather than a solid black tie. Wearing black isn't so much the norm for funerals as it once was, but make your decision based on the customs where you live or where the funeral will take place. You are honoring your friend, so if wear something she would like!