As a Canadian I had to take a lot of French courses and I think I remember
Asterix being mentioned in one of my workbooks. However, I can't think of an alternate name for it.
As for
Doctor Who, I would say, "Doctor Anonymous" since the doctor doesn't have an actual name and because of the fact the doctor "has the ability to regenerate when his body is mortally damaged, taking on a new appearance and personality." (I looked up that last part on Wikipedia)
In regards to
Seduction of the Innocent, I might suggest something like "Temptation of the Youth", since that whole thing was about comic books supposedly causing juvenile delinquency. I also had to look that one up.
For the Clint Eastwood films, I might go with " A Handful of Cash", "For a Few Bucks More" and "The Benevolent, The Malevolent and the Repugnant". Okay, I think the last one might sound a bit too highbrow. Anyways, you can go a whole bunch of different ways with
The Good, The Bad and The Ugly if you use a thesaurus.
I can't think of anything for
Gladiator, plus I'm not familiar with it. As for
Thunderbirds, maybe you could go with "Super Marionettes" since the show used something called
"Supermarionation".