What we'd like to do is ensure that the client would have control of the name, such that if this licensee were terminated, that we could control the domain name and not have to chase after it. We would want to enable them to have enough control to manage their web site but it sounds like this might be difficult from a technical perspective.
The domain name at issue is a "com.au", so we would have to register it with the Australian registrar for this ccTLD. I'm not sure if that makes any difference.
If you mean give someone else access to the server so they can FTP new pages and changes etc, then this is a common situation. The owner of a business (and hence the domain name) is often not the person who works with the content hands-on. And because the am not the owner, Ithey can't transfer the ownership to anyone else through the registrar, but they do have access to all the hosting aspects of the website operation.
It's the difference between registering a domain, and working with the server that hosts the domain. All you need to do is give the third party server access to the host server (address, username and password).
This is fairly common practice. We often lease domains to third parties. We point the nameservers on the whois to them, it it is their responsibility from there.
As long as they do not control the email address asscociated with the whois records and have no access to the account at your registrar, they will not be able to hijack the domain.
HTH