Sure you can make an MTM/WTW styles speaker with these, but you should know that horizontal speakers have drawbacks on sound stage, etc.
With that said, yes, you can move passive radiators to other sides of the box. Generally that will not be an issue.
You may want to adjust bracing accordingly, then account for any extra bracing with extra internal space (de minimus changes won’t significantly change things though, so if only changing position, not adding extra, no need to change the outsides of the box for more internal space).
