As for during the writer's strike, I believe they could still film what was written. They just couldn't write more or change the script. So I;d guess the idea might have been to film as much as they could, then do rewrites and reshoots after the strikes end.
Talk shows are scripted. Scripts are written by writers. If non-union writers wrote the scripts while union writers were on strike, that's scabbing by definition.
Everything I've read has suggested Drew Barrymore was going unscripted until the WGA strike was over (i.e. they were fully working within the terms of the strike).
I hadn't heard that she was intending to go unscripted, my apologies.
In my opinion, that's an attempt to find a way around the strike and to cut writers' labour from the equation so I would still consider that to be roughly equivalent to scabbing, but I realize that not everyone thinks that way.
Based on this article, yes and no. A writer improv-ing is the same as writing changes. An actor without a writing credit could still improv. Thanks for verifying
Yes and no? Improve is off the top of your head and is usually an acting method or exercise.. writers do not improv. the writer may give prompts to have an actor or speaker go off the actors own ideas, but there is no structured writing and ideas coming from the writer going into the content of the improv exercise or method.. whose line is it anyways, is a good example.. there are prompts for the actors, but all content came from the actor themselves.
Deadpool 3 is filming using a shooting script written by WGA members. Barrymore and Maher would have started filming with themselves replacing the work their writers would've done.