Yes. The Minx speakers were designed to be mixed and matched without a problem.
It is best to ensure that your 'pairs' of speakers are the same (ie front left and right) but there should be no issues.
You can also add the newer Minx Min 11 and 21 to systems with the Minx Min 10 and 20 speaker without a problem. If you are doing so, for best performance, move the newer speakers to the front.