Mixing front and center

For primarily music or movies?

If the former and for personal listening, those Dynaudio's should image like mad, and I'd wonder the need for a center.

If for group music listening or movies, you'd benefit with a center.  But I'd venture to guess with the driver differences between the two, you'd notice timbral differences across the front stage, especially when sources pan across.

I would sure try to match the brand and even series.  However, I ditched midfield surround for great two channel, and not only does the music sound way better with dedicated 2 channel replacing the AVR, but the videos sound, with excellent imaging, sounds better too.