Customers would find it very useful if the contacts in Unleashed and Prospect were linked. So if they create contacts in Prospect they would want them to populate in Unleashed and vice versa.
Right now it only pulls through to the CRM the primary contact. If it had that contact at the point of when the customer was created. If the contact was added after creating the customer's account say 2 days later it won't import through.
The unleashed API has been updated and we've started syncing unleashed contacts into the CRM and sync'ing them (if you turn this feature on in the options). Soon we'll add the ability to push multiple CRM contacts to unleashed too.
Unfortunately, at the moment the Unleashed API doesn't provide access to any additional contacts information so this isn't currently possible. Any Unleashed customer looking for this functionality should/could perhaps "up-vote/push" Unleashed for that feature to be added to the Unleashed API