I've got over 70,000 miles on my 2012 DL650. I've only had a front tire the same as the back twice - and that was a different points of tread life front to back, thus never a set starting together. I replace them as needed - unlike some devotees who replace front and rear as a set each time. I find a tire I like, then usually by the time to replace the other, I've gotten interested in trying a different tire, or didn't quite like one thing or another about the last choice. So, mix as you will. Even "matching" tires in a set are different sizes, inflation, and have different jobs on the bike, so the idea of having to match them is not justified in my opinion.
I would suggest you keep it generally the same style of tire to get predictable handling. For example, if you run a popular 80/20 dual sport tire on front, pick a dual sport tire for the rear. A dirt tire rear and sport-street tire front would limit you on both dirt and street.
We're all here, 'cause we're not all there