Soundtrack Instrumentation?

[TheRealThem]

What do Jason and Vince use for their instrument sounds in this game? Do they use a sound library, or does Klei have the budget to hire Musicians to play it, or did they by some miracle find good-sounding electronic emulations of real instruments? If the latter or the first of the three, which one(s)? I was wondering because I was considering writing fan music for Don't Starve, and It'd be ideal for it to sound as much like the in-game music as possible. Also, they're just all-around awesome sounds that'd be useful for any songwriter in any situation.