Ashod,
You have just discovered one of the drawbacks to your organization's security design. It is much easier to decide which roles to assign to users when tcodes are only granted by one role. I know, that does not help you right now, just something to keep in mind for the future.
If the role design is job based roles, it helps to know what job(s) the user is doing, so you can see which role(s) sound the closest to the user's job(s).
A method that can be a good shortcut is to ask the user (or his/her manager) if there is someone else in the workgroup who has the access your user needs, and do a Model User request. or, use SUIM to look up the roles assigned to the potential model that grant each of those tcodes.
When all else fails and you still have no idea which roles to request for the user, you might be able to appeal to the respective role approvers for assistance ( assuming these roles all *do* have a role approver requirement, and they have been doing this longer than you have, right?).
This is why it is helpful to have some job aids for the persons tasked with submitting security requests for end users when the role names are not an exact match to job titles, until such time as the organization can do a security rewrite to align them better, either at the task level or the job level, or create Business Roles in GRC that do exactly match the job titles.
Good luck!
Gretchen