I have seen some mix and match. Can you run an av72 in rear and elite on the front? Any issues with this?
People have been known to mix all sorts of tires, so obviously you can. The important question is if you should. Tire manufacturers will tell you, and I agree with them, that you shouldn't. Different brands with different compounds and tread will handle differently, which can throw off the balance of the bike. It may not be a problem for the casual rider but if you plan to push the limits of the bike you could regret ignoring the experts.
Btw, while you're looking at replacement tires are you just looking for something that will fit on the rim, or are you considering everything including load ratings? Many of the tires on the market that will physically fit your rims carry a significantly lower load rating, since they were originally designed for much lighter sport bikes.
Jerry