Are you going for an accurate representation? If so, then modern kilting material would not be correct for the period. Maybe for the 19th century, but not 18th. Celtic Croft sells a homespun material that I think more accurately represents the material of that period. But it is not 100% wool. Woodsheal might have a better opinion on that. And again, if you are going for accuracy, stay away from modern clan tartans. They did not exist then. There are some tartans that are pre-Culloden, so look for those.

As for jackets and waistcoats, it's usually made by individuals in their homes. These are usally hand made and made to measure, so be prepaired to pay a premium. The links already provided are your best bet.