When meshes have been frozen in the scene, it exits very early from _evaluateActiveMeshes(): alwaysSelectAsActiveMesh is used later in the process and so won’t be of any use in your case.
https://www.babylonjs-playground.com/#92Y727#3
I freeze meshes after 2s and animations are restarted after 4s without meshes being unfrozen.
I’m unsing skeleton.prepare() to make the animations running “by hand”. It’s what _evaluateActiveMeshes() does, so it can’t be totally off the mark 