Is there a way to add identitylinks via service task in the middle of the workflow process? DelegateExecution doesn't seem to support that. It looks like it can only get/set variables?
You can get access to the engineServices() and add identityLinks through there. You can also get and cast inner classes (eg identityLinkEntityManager) to do what you need (but then it's of course Activiti internals you're in).