custom reports

Can you tell me if we can run the following reports:

duplicate entries: we think we have a few records that are entered more than once in the system. We think they have the same first name or surname or date of birth or address. Is there any way that we could generate a report of people with the same first names and surnames, for example, or people with similar first and last names but the exact same date of birth?

custom field: we have a custom field called “marketing profile” and the entries possible are: 1,2,3 or 4. Could we have a report generated of people who have definitely had an appointment and have a marketing profile of “1”, for example?

thanks for your help.