Much the same as non-Jacobite's of the same time. Kilts/Plaid for the Highlanders. Breeches, coats and stockings for the Lowlanders.
braces
Yes, Celts do wear kilts. However, Celts typically originate from Ireland. Kilts actually originated from Scotland and the Celts just took over the fashion trend.
kilts
they don't - Scottish men wear kilts on special occasions. Irish pipe bandsmen wear kilts only when playing music
Kilts
Kilts.
Scottish
cloths or kilts
Since the middle-ages. Also, it's 'Scots' not Scotts.'
Very few Irish People wear kilts, it is really a modern Scottish phenomena. The only people to wear kilts are pipe bands etc.
Kilts are the traditional dress of the Scotland. They wear kilt to show their culture and history, but it is not restricted to wear a kilt only in Scotland. So anyone can wear it, thats why people from many other countries wear a kilt and shows their interest in wearing a kilt.