SAT 1. is the 3th biggest channel in Germany (in the target group of people between 14-49 years)
RTL 2 is number 8
Here the proof: http://www.quotenmeter.de/c/136/tv-jahr
SAT 1. is showing shows like "The Voice of Germany", "Homeland", "Criminal Minds" and "Elementary"
In my opinion there is no question, SAT 1. is the more powerful in this comparison. They have also the most watched morning show in Germany, called "Frühstücksfernsehen". This will be a great opportunity to promote Celebrity Big Brother to a lot of people.
A channel's spokeswoman said that they will use some kind of big brother house for sure. Seasons 8 to 11 were produced in the same location. It was a TV studio in cologne. The studio is a part of a really big compound of many studio's, called MMC (Magic Media Company). The former Big Brother house is studio no. 50, it's been used by a different TV production (soap-opera). So I can say for sure that there won't be another Big Brother house in that studio.
But there are many other studio's which can be used as a possible Big Brother house. All these studio's must be rehired by the production company and/or the responsible channel, because the MMC is a single company that makes its money with renting its studio's.
However, they can use one of those studio's and build a "fake" house in it, or the build a "real" house outside. Endemol is located direct next to the MMC so I think the new house won't be situated far from this place.