I've always thought that Croatian football fans look spectacular in their red and white checked shirts and especially so when they are all waving their simple red and white checked flags.
So here's another two suggestions. One copied straight from the Croatian fans with the orange being the setting sun and the other with the same orange and with the blue being the sea (also famous CBF colours of course).
Perhaps supports of the carnival could have tee shirts made with some of the proceeds going to the charity.
PS A finally thought on my first flag if I may. Although it may lessen the effect, would it be any less offensive if the colours were changed - say blue crescent and star against white background (think it's the case that there is a flag with white crescent and star against blue.
That's it from me, I'll shut up now.