Question re: Permissions access via HDD enclosure

Hello,

Finally getting around to installing a SSD in my 2011 MBP.

My current drive is a Seagate 1TB Hybrid Drive (736GB used), and the new drive is a Sandisk 240GB SSD. Obviously with that space discrepancy, restoring from a Time Machine backup would be impossible.

My intention is to simply install the SSD, clean install OS X 10.11 El Capitan GM Candidate to the SSD, insert my old hybrid drive into a HDD enclosure, hook it up via USB, and transfer the data I need. There are two accounts on my current machine - mine, and my girlfriends.

My question is this: when I access my old hybrid drive via USB, will there be any problems accessing my girlfriend's data? She has a lot of pictures and also edits a podcast, so it's critical I don't run into any permissions problems along the way. I know that if worst comes to worst I could just re-install my old hard drive, log in with her credentials, copy the data to an external, reinstall the SSD, and copy the data to the SSD from the external, but it'd be a lot easier if it could be done with the method I initially described.

Any and all comments are appreciated - thank you!