How can I make files available to a restricted profile? For example I have an emulator and I want the restricted profile to have access to the ROM directory but it seems like the restricted profile has it's own directory structure separate from admin.

I foresee similar problems with any side loaded media like video, audio, eBooks, etc.
Put them on the SD card. App data on the internal storage is completely segregated between users (regardless of whether they're full or restricted users), but there's only one SD card for all users. You can add a fake SD card to an emulator: it's another file on the host system, like the fake internal storage.