The 8/18 news is simply pointing to the two fandisks being released on August 29th. The two DVDs are similar, and each contain a bunch of characters songs, an anime short, preview of the OVA, and some audio commentary. Like all the CDs and stuff, you'd have to collect both DVDs to get everything (the answer to "why not put it all on one disc if you're going to release both on the same day anyway" is sort of obvious...).
Regarding the OVA series, it says there'll be two volumes, with the first being released (as we already knew) on November 28th. The first volume will contain two half-length episodes (total running time of about 30 minutes), along with an extra short.
They really like the number two for some reason, because pretty much everything comes in pairs.
