Downstairs toilet on coach upgrade?

[G0HWC]

I have a Van Hool coach that is being re converted into a motorhome. It has a downstairs toilet and looking at it today it can easily be made more spacious just by squaring it off.
Has anyone else done this?
Looking for suggestions on what toilet to fit etc.
Would also luke a shower in here

 

[scotjimland]

The existing toilet will have a waste tank below it, like a portaloo ?