I can't resist adding that the last Funeral I attended I wore my thrifted Black/White Chanel dress (!) That said, I don't think I would wear it to a close family Funeral, as I want the memories of wearing it to be happier.
Otherwise, in Australia almost anything goes, but I like the idea of a sheath dress and dark topper.
I did have a dark suit once but it was only worn to funerals and was dated and ill-fitting.

My go to has been the Ann Taylor outlet. Both of my suits are from there and they work well for funerals and special occasions. All I have to do is swap out the top I pair with the suit (sequins for fun, a black or white shirt for a serious event).

Lyn - wow, an outting for the chanel sheath. I can pretty much guess you were the most stylish but appropriately person there. That is such a special dress that I can see wanting to keep it for happy memories. Kind of a tough choice. I never thought about it but yes, I can see having one outfit or even a teensy capsule of sad occasion attire but that might make me feel even worse. I think of a black suit as all purpose respectful and actually think I'd be happier if I wear it for good special and not so happy special - kind of like balance if that makes sense.
Lisa - I love a suit too I am desperate for a new one. The two sheaths I ordered from AT were a bust. Talk about vanity sizing they were huge!! I am going to have to buck up and get on this. Hoping something perfect will appear!! Glad you are set with your suits, such good investments and so useful and appropriate!! Lucky girl!!