chicken shish kabobs the night before cooking
Having the vegetables and meat marinate or assembled together is fine, so long as the finished item is thoroughly cooked.

When grilling skewers, you cook long enough to have the meat to a safe temperature, so the vegetables should be cooked through by then.

For greatest safety, make sure there is a little spacing between the items on your skewer, and if this is not done make sure they are cooked through.