There is a musical notion of turning some random humming into a very big orchestral swell. For it to work It would need some humming in a time range 80bpm and it would need to be a fairly clean tone (no vocal fry) with a simple melody line.
The liemotif would begin in part of a random stream and then become more defined. The options for composition are either random humming something and we build around it or I can send you some piano lines of melodies to hum should you wish to have a go.
Well wishes and esteems