You can pick your tow car based on your camper or pick your camper based on your tow car... and you're already committed to the tow car. So you're asking too much from your hypothetical camper: tiny (lightweight) but with an enclosed bathroom that isn't stacked inside its shower?
Decent space with light weight means a pop up, which means a fake (if any) bathroom. We made our own: we have a Coleman camping toilet in the nook to the right of the door and run a shower curtain across to close it off as needed. The bed areas have their own curtains too. It's us in the king, one kid in the double, one in the dinette. The dog can come too.
And looking at this page, my camper's a lot lighter than I had thought. Good news, because we fill it and have boats strapped on everywhere.