You can try that but I don't think it will help the center itself. Bass management will redirect appropriately and Dirac Live should handle phasing everything for you.
My concern, based on limited personal trials, is that you'd need to cross the C205 up around 100 Hz to really keep it happy, and content below that will go to the sub (not the L/R speakers -- see below). That means you could still have significant energy up around 150~200 Hz to the sub, and that can spread the image (unless the sub is under the center speaker). It also takes away from the center's lower end, which to me led to a bit of weirdness with a sort of "light" (not nearly so far as "tinny") center sound. Much of my HT's life the center was crossed higher than the mains but I prefer a more seamless front stage.
Note that unless you have a very flexible processor (think Trinnov) you cannot redirect the lower center frequencies to the L/R speakers, only to the subwoofer(s), so the L/R speakers can't really replace the center. Bass management takes frequencies below the crossover from any and all speakers to the sub(s), not to other speakers. I do not think crossing the mains lower will help the center though there may be other reasons to do so (countering room modes, preference, etc.) I had a small center in my first HT setup and ended up getting one that played deeper to get a better front sound stage. Compared to the F206's the C205 is, again my opinion, a step back.
Another option is to skip the center and just use L/R speakers to create a phantom image. I've done that too, but so much is in the center that I feel a HT system really needs one. Without the center it is harder to "anchor" the video, and sound outside the center sweet spot is much worse, than if a center is in play.
Again, all in my opinion; others do all sorts of things and are happy with their systems. Preference along with aesthetics, cost, and all that jazz matters.
HTH - Don