Question

I guess the question says it all.

I’d really like to be able to use this older mobile interface with my iPad on the go.

Answer 1

iOS does not have native 1394 support. FireWire to USB converters don't exist, even though there are 1394 to USB gender changers these do not work (just because it fits doesn't mean it will work).

If you want to use your older 1394 interface on the go, you will be better off finding a refurb MacBook that was supported when the FireBox was new.