Some European collections have successfully mixed Saki with Squirrel Monkey. So another potential option (given that Squrriel Monkey are already established and doing well in Australia/New Zealand)
The Debrazza are a bit of an odd choice though? Surely if they wanted a medium sized West African primate, then they'd be better off teaming up with Adelaide to increase the number of Mandrill and/or Colobus within the region rather than importing a third species? Both Mandrill and Colobus are available from Europe or the USA (in good numbers, Mandrill breeding is very limited in EAZA at the moment due to a lack of space) if desired.
The Debrazza are a bit of an odd choice though? Surely if they wanted a medium sized West African primate, then they'd be better off teaming up with Adelaide to increase the number of Mandrill and/or Colobus within the region rather than importing a third species? Both Mandrill and Colobus are available from Europe or the USA (in good numbers, Mandrill breeding is very limited in EAZA at the moment due to a lack of space) if desired.