"Does anyone know if it is possible to differentiate these roles. . . ."

The roles, by definition, are differentiated. Do you mean differentiate each
SharePoint role  so that, for example, the Coordinator role might be split
into two or more sub-roles?

It would help, however, to know what your requirements are ('demand list')
to answer your question. It could be that SharePoint is not right for your
requirements.

We have the same problem with SPS. There is no way to separate the roles
and permissions. However, if you use Active Directory you should be able to
limit permissions such as delete. The only catch (of course there had to be
one) is that the option still appears to the SPS user. For example, if you
remove the delete permission from a user, the delete link is still an
option. They tell an access denied error, but if you want to remove the
option you have to remove the link.

Unless someone knows of a better  way! We're all praying V2 allows us the
ability to have non deleting authors etc.

Any ideas on setting up access for a user to respond to a survey and or
update a doc library but not have access to do anything else?