I have a Pirelli Angel ST on the Rear and a Pirelli Diablo Strada on the front. My rear was shot but the front was in really good shape and I couldn't see trashing it. The dealer "recommended" that I replace both because I shouldn't mismatch the tires. I declined. I understand that they are trying to make a sale but.....no. I have had no issues whatsoever in over 1000 miles. I don't think my mismatch is too far off since they are from the same manufacturer.
That bolded assumption is very risky. Tread compound, tire type, speed rating, profile, etc can vary just as widely in tires produced by a single manufacturer as in different brands.
In general, I would go stickier front rather than stickier rear, if there were to be a mismatch. FWIW, IIRC the devil is a stickier tire than the angel, so you s/b fine.