Corylus Maxima Purpurea + Corylus Avellana viable ?
 

I have planted a small Corylus Maxima Purpurea near a small Corylus Avellana
Contorta and alongside another ordinary Corylus Avellana (currently with one
nut on).

What is the possibility of cross pollination between any of these varieties
leading to Hazel or cobnuts on any of these bushes in future years ?

Anthony