You should definitely review Appendix B.
We enter our loan applications directly into an LOS when someone comes into a branch to apply for a loan. The applicant does not receive a paper application to fill out. Do we only request and complete the aggregate data?
You have to request the data, and you have to report what they say (not just aggregate). If they don't want to provide the information in person, then you have to base it on visual observation/surname and only use aggregate categories.
If so, am I correct in stating that the only time we would ever have subcategories is from a written application/demographic information form completed by the applicant whether it be online or otherwise?
No. If you ask for ethnicity and they say Brazilian, then you need to report Brazilian. I'd argue you should(arguably must) walk them through the form orally if you aren't providing it whether in person or on the telephone. I would definitely just give them the form.