What might be best is maybe a sienna reclining bucket in the back
Behind the driver, then Wesley could even sleep in it since it fully reclines.
Or even a short 2 person bench like a shuttle bus would have. Would be easier to move around in there.
As for hauling bikes inside with a bed platform, I struggled with this concept early on, grant it, my 650 is a lot bigger than the pictured pw50 and what looks like a ttr90 or 125 small wheel, but I decided to toss mine on the back. If I wanted a convertable space, I'd box in my wheel wells 6' long and hang some vertical e track to the plywood boxes, you could then make a stowable platform that set into some e track fixtures and toss the mattress on top.