There's a big hole for a bluetooth module, if you can find a pic of a Velocifire board with it populated you can find a module that matches and solder it on. It might just work or you might have to update the firmware to that of the bluetooth version.
I'm not seeing any pads for underglow RGB LEDs so there's no reason they would be included in the firmware and you can't add it. You could solder the 'in switch' LEDs of the edge switches underneath the board to add single colour underglow, looks like the resistors are already soldered for them.
The only Hasu board that might be of use would be the USB to USB which is used to remap keys on any board - it's very nice but won't help with either of the above.