I saw you mention the music in TFA and I was curious if Finn had a theme in the movie? I remember seeing Rey's but I don't think I've seen one for Finn but maybe it's not titled with his name? If he doesn't I hope he gets an awesome one in viii.
Interesting question! I did some digging and this is what I found:
1. The soundtrack doesn’t have a song titled “Finn’s Theme.” There’s just “Finn’s Confession” which is beautiful.
2. John talked about visiting during a scoring session and how “it’s crazy to have your own theme people.”
3. Articles on the soundtrack make mention of a theme for Finn but mostly as a motif showing up in different pieces that could ultimately be extended in future movies:
Finn’s theme is rhythmic and energetic, and just a little chaotic, which is a perfect representation of his character; as a Stormtrooper rebelling against his masters, Finn has never before experienced life outside the strict regimen of the Imperial military, so his sense of bewilderment and wonder at his new circumstances is quite rightly overwhelming.
 It first appears at the 1:12 mark of “Follow Me,” runs through the rest of that exciting cue, and appears later in cues such as “The Falcon,” and “The Rathtars,” accompanying Finn’s most prominent action moments. The way Williams jumps between Finn’s theme and the Rebel Fanfare in “The Falcon” is breathless and brilliant.(x)
The renegade Stormtrooper does not garner any consistent form of melodic identification. However, a jerky 11/8 rhythm attaches to his exploits early on, a kind of “man on the run” motif.
This rhythm is easier to hear if you produce it yourself. Try counting this pattern quickly, always emphasizing the “ones”:
1-2-1-2-1-2-1-2-1-2-3, and repeat.
Since Finn will remain a central character in Episode VIII, it’s likely that his thematic material will become more clearly drawn in sequels — as was the case with Darth Vader between Episodes IV and V. (x)
In conclusion, there is a distinct motif attached to some of Finn’s actions in TFA but the soundtrack and film did not reveal a full theme as of yet. One could be in existence (if John heard more than the snippets that are in other songs) to be drawn out in upcoming films. If we get to hear it in the next film, you can bet I will purchase the soundtrack and play that baby on a loop for weeks and possibly choreograph an interpretive dance to it :)
