Can you tell me if my miniart Swiss can be used with the Red Box sets?
Rather not. Different dress, armour and hairstyles. Miniart Swiss are meant to be of the 1470s to 1480s, Red Box should be c.1510-1530. As if you'd mix Seven Years War and Napoleonic French. So whether or not you combine them depends on your attitude towards historical accuracy.
Re: pictures and boxart of the new redbox swiss and landsknechts
Hurray for Redbox, They have listened about not having telegraph pole pikes and giving the pikemen open hands. I hope they line up well. We are finally seeing one of the last great uncovered periods covered in 1/72nd, and covered very competently by the look of it.