You can always find room for a couple of needles, safety pins, tweezers from a SAK, and a fish hook or two.

Wrap the firesteel with some fishing line. Even a few feet can be used as a less visible leader and use a strand from your paracord as the main fishing line.

Stuff some tinder from a Spark-lite in as well.

Perhaps an ACR flat whistle would fit, esp if you traded out the firesteel for a Spark-lite which may be smaller?

Or maybe a couple of Micro Pur tabs and a gerber milk bag?