Acceptable to use Antelope and Barracuda simultaneously?
I wrote a post 3 years ago that discusses this very subject : innodb_file_format Barracuda

In terms of storage, using Antelope and Barracuda is possible. However, in my post, I discuss a residual effect on the InnoDB Buffer Pool. You need a larger Buffer Pool because Barracuda compressed pages in the Buffer Pool have to be decompressed to the read in the Buffer Pool.

You should dig deeper through Percona's Performance Blog site for any additional insights.