Canon bodies are designed to work with Canon lenses mounted directly on them. So if you think about it for a bit, it only stands to reason that interposing another camera between the Canon body and lens -- be it an Actus or a Universalis -- means the ability to achieve infinity focus will be lost, the same as if you had used an extension tube.
I couldn't have said it better myself.
The only option you have that will work if you're using a Canon body on either the Actus or Universalis is to use lenses designed for medium- or large-format cameras that have a lens register that is long enough so there is room to squeeze one or the other cameras in between the body and lens and still achieve infinity focus. I'm fairly certain this will rule out the lenses with shorter registers (Mamiya 645 and Contax 645 come to mind) but it should work with Hasselblad V and all the other medium-format lenses and most large-format lenses as well.
When it comes to the Actus system:
Your Leica should play nicely (be able to achieve infinity focus) with Legacy M645 lenses, Pentax 645, Hasselblad CF (V-Series lenses), or Mamiya RB/RZ, and Large Format lenses appx 70mm and longer.
The Canon is a little more limited to Hass V, and RB/RZ. As well as large format lenses 90 and greater.
Hope this helps a little bit.
**Edit**
I also completely forgot about our Actar series of lenses as well. Both systems should be compatible with most of them (the Actar 60 being an outlier that only works on Mirrorless bodies). 24, 80, 90, 105, and 120 should all work well with both Leica and Canon.