The Burrow themes are based on Mezeporta Wind from Monster Hunter Frontier (Day and Night, pre mhfg), they're a soundfont cover by my friend Zeocin ^vv^ We're really glad you like it!
The main Burrow themes are just Mezeporta Wind (the ones that play when you are walking around/returning and turning in subquests) though the night one does have some motifs in it
I do use Wigglytuff's Guild and some others for cutscenes and the morning briefing though!