Hi Any,
About Option1, yes the CA WA WebServices is mainly an API for DE. It can make SOAP calls to DE and you can control your workload. There are few functions, that are only available in Web Services.
However, CA WA Web Services will not add to your agent count. This is not an agent, but a client. If you are referring to CA WA WebServices Agent, then that is a separate from CA WA WebServices. You don't need the Web Services Agent to work with CA WA WebServices.
The other thing I can suggest is that whenever you run something as a script, you have limited control over it. If we have a job type to run the process, the CA WA Agent (and manager) have better visibility over the process and job.
HTH,
Nitin Pande
CA Technologies