I don't know who you are going for but I really doubt any one in Oz will ask you specific detailed questions about a type you don't operate.
If they ask you any thing about the Dash 8 it will be general stuff that Bombardier should be able to supply on the website. Eg engines (types/SHP etc), number of seats, variants used by said airline, routes flown etc - get that one from the airline's website. Know some aerodynamic stuff such as the deep stall as it is applicable to a Dash 8.