Can you add engineer figures to Williams scale GG-1 interior cabs?

[N.H.&I.railfan]

I recently purchased three new Williams scale GG-1s. How can I remove their shells to place engineers inside the cabs? Is this doable? Is there enough room to place seated engineer figures inside a Williams scale GG-1 cab? If you have already added figures to a Williams scale GG-1 interior cab, which manufacturer's figures are the best to use for both fit and size with minimal kit-bashing modification needed? Thanks in advance for your replies.

[phillyreading]

You need to see wether you can add in a figuire first of all, then find out if you will put in an O scale figuire or an H.O. scale figuire as I did in some semi scale O gauge passenger cars.
You may have to make a base or platform for the figuire to rest on, then glue the figure in place, also you may have to cut part of the figuire to make it fit in a small space.
I went to my local hobby shop and bought some figures, don't remember what brand. Not sure if Artista or Woodland Scenics.

Lee F.