I can tell you right now one of the questions will mostly likely be..
"Tell me about a time you made a difficult decision?"
And I was interviewed as a PA.
Where you approached by anybody to be a GSA?
I'd imagine a GSA/PA's interview is roughly the same. They want you already, will ask you questions where they don't really care about the answers. Then they will tell you why your job is so important. (This was with my ETL-HL, now SF).
My interview with my TL was a joke, because they asked me to apply, lol.
If you are just applying, a lot of the questions will center around your previous work area.
"Tell me about a time you went above and beyond for a Guest/TM etc.."
Pretty much just rehearse and remember your most stellar moments.