At least two other season 8 eps have been mentioned before and while the shootings of the current season.
The first one will have Little Jack and Maybourne in it.
The second is the episode written by Chris Judge, also know as "Big Fat Jaffa Wedding" ( I don't think, they have time for a wedding in the episode "Sacrafices")
This leaves only 6 eps for the missing characters and aliens.
I would really like to see the Furlings!!