Ok, I cured them with the help of an UV light source.
Mdf to mdf joints obviously doesn’t get the needed UV light so they may not have been fully cured. But they were dry. No real bond there, as expected.
Mdf to acrylic sticks to some degree. The joints still come loose without much force but the surface of mdf may stick to acrylic.
Beeswax seem to stick to acrylic to some degree. Still easily removable but affects the surface.
Paraffin. Lifts easily from paraffin treated mdf. And paraffin doesn’t stick to acrylic.
So, based on this highly unscientific test, I would do a test piece resembling the real mold and treat it with paraffin.