GUI slider for complex rotations + combining sliders

Hello everyone, my loaded model has a skeleton and I would like to control (via dat.gui) some of its bones.

aBone.rotation // Object has properties { _x: 0.612..., _y: 0.048..., _z: -1.228... }
aBone.rotation.set( .15, 0, -.85 ) // This would be the values to transition to

I would like to add a 0→1 slider transitioning between this two values.
Please how should I go since 1) this aren’t single values (it affects x, y and z) and 2) they are complex numbers and not only 0 and 1 (x goes from 0.612 to 0.15, …etc)

Moreover, I already have a slider for a morph, like so:

let folder = gui.addFolder( 'Morphs' )
folder.add( model.morphTargetInfluences, [0], 0, 1, 0.01 ).name( 'Blobby' )

Would it be possible to have one slider that affect both at the same time, rotations and this morph?