Has it been disproven, or was it abandoned as being his theme? I honestly had never heard about it before, and am curious if there is a legit source…
Does Finn have a theme in TLJ/TRoS? Does he have a theme at all?
There was never a source. People just speculated that it might be his theme since he was in the scenes featuring it, and the other new characters (Rey, Kylo, Poe) each received a theme. But the evidence is against it since there are moments in the film that are Finn specific without anything like that motif, and Williams only reprised it once in the next two films (when BB-8 fixes Poe’s X-Wing in TLJ - nothing to do with Finn). Since Williams reprised every other new theme he created for TFA, it seems unlikely that he would abandon just one.
More likely he didn’t have a theme, and never got one. It wouldn’t be unusual, Lando never got a theme, Padme never got a theme, Obi-wan and Luke’s themes both became more general, and Han didn’t get a theme until 2018.