Discussing with @PE0SAT in the satnogs chat, I’ve realized the narrow signal is the default music transmission from endurosat comms. Thus probably don’t belong to CUBY satellites, a similar one at 435.5470 MHz for the “Unknown 1 T17”.
So, probably we are looking for the 5 CUBY sats and to find out which one are the satellites with endurosat transmissions at 435.595 MHz and 435.5470 MHz.