Turns out that "The Most Mysterious Song", the one that was featured in MyHouse.wad somewhat recently, was found after 40+ years, it's "FEX - Subways of Your Mind", it's all over the YT now, the band members are alive, plan to reunite again for the cause and have already recorded the acoustic version with a partial lineup.
I wasn't involved in it and haven't really followed it, but it's probably the best ending one could wish for.


If only one of the searches and investigations I've participated in had ended with such a lovely outcome. If only.