Yes, task engine based on WS-Human Task specification is part of jBPM5.
- Does the BPM Suite provide templates to create human tasks? (If yes, please describe each of them briefly)
You mean forms for human tasks? This should help: http://blog.athico.com/2011/08/jbpm-form-builder-integration-make.html
- Is it possible to pause and resume tasks?
Yes it is possible. You can check this operations to tasks here: http://docs.jboss.org/jbpm/v5.2/userguide/ch.Human_Tasks.html#d0e3781
- Is it possible to run tasks in parallel?
Tasks are independent, so you can run tasks in paralell.
- Is it possible to accept, reject and forward tasks? (Functionality provided out-of-the-box?).
You can foward tasks. Accept a task would be claiming it. And I don't know reject.
- Is there a central task management concept/solution?
Yes. A task server is a separate concept. The jbpm runtime will communicate with task server to create tasks, and then you can use the task service API to manage tasks lyfecycle. (http://docs.jboss.org/jbpm/v5.2/userguide/ch.Human_Tasks.html)
Hope this helps,