Blutooth Headphone Media Controls
This information IS in the Safestrap for the verizon S4. However, it took me three times of reading through the OP material to find it. I have also seen numerous questions from hyperdrive users. For the buttons on bluetooth headphones to work the current ROM has to be in the stock slot.
This is not a ROM issue but a limitation of safestrap. If the ROM and the headphone controls are that important wipe the stock slot and flash a TW ROM, flash modules and enjoy. There are dangers with wiping the stock rom (bad download of new ROM etc.) but I and others have done it without issue.