They are exactly the same, made by the same company. I purchased the Bowens and used a Profoto RFI speed ring adapter plate (just the silver part with the mounting mechanism). It worked but I had to drill new holes in the adapter plate right along the edge of the circle. I'm not sure how different the actual Profoto adapter plate is versus an RFI speed ring adapter plate. I would assume for cost they would use the same thing, but who knows. The price difference is ridiculous, the quality is also not that great.
The iris you mention is only made for the Zoom Spot which is not the same as the Small Spot. You can cut your own shapes to use in the Small Spot though.