I would go for a waistcoat,the 3 button one,too.You can then forgo the dress belt.If you can, try and get the waist coat half to one inch longer(not any longer though) than you think you need,it will help hide the join between the kilt top and waistcoat and thus avoid the unsightly sight of your shirt poking out.

How about shoes? You do not need those awful ghillie brogues, a well polished pair of black shoes will do nicely.Have fun.