As the OP stated, bootloader is locked. End goal is stock ROM, recovery, locked bootloader.
The only way I can think to flash something with a locked bootloader is in RUU mode (fastboot OEM rebootRUU, fastboot flash zip twice). However I've only ever seen flashable CWM/TWRP zips, not stock recovery. Maybe Guru Reset ROM can be flashed this way? I dunno if Aroma will work and if you'll be able to select to flash recovery.
A little bit overkill, but is there an OTA file for your region? The firmware.zip in the OTA will contain your stock recovery.
---------- Post added at 05:08 PM ---------- Previous post was at 04:54 PM ----------
Wait.. You're S-OFF and you've already removed the tampered flag. What's wrong with:
1. Make sure bootloader is unlocked, and have custom recovery
2. Flash guru reset ROM, selecting stock ROM and recovery
3. fastboot oem lock