Aggregate the data into an Access database." If you're just using some database as an intermediary to SQL, then, because you're dealing with Excel spreadsheets, you probably want some kind of hierarchial database, not Access.
I'm not sure what "aggregate" means in the above statement, but Access is a Relational Database. I see this all the time in companies - people "copy and paste" an Excel spreadsheet into an Access table and stop there. This is not correct. You must then NORMALIZE the table. One spreadsheet may (and highly likely) will create multiple Access tables. And since you stated "identical formats", you're probably going to have duplicate data all over the place. A no-no in Relational Databases.
In the above post, option 2 would be the way to go.
Whichever way you choose, the final tables in your database (SQL, Access, Oracle) will have to be Normalized. That's why they were invented - so you can query data through programming and not structure.