Spirits of the snowponies who perished in the wilderness and hence couldn’t find their own way home, following the beacon created by the shamans to guide their way.
Yes that is a snowfilly spirit cozying up to her alive mom, and dead snowmare hugging her foal, both having perished in the unforgiving cold. She wasn’t able to save her, but it’s okay, as they’re reunited now and will step into the afterlife together.

You are now imagining Cirrus Wisp singing to the spirit of the foal as she leads her towards Snowpitt. It is one of the ancient songs she’s so seldom afforded the chance to sing to foals; not quite a lullaby but crafted to soothe a worried heart. A song the foal’s mother sang to her when she still lived. Not all souls rest so easily, unfortunately, and particularly those of foals taken from their parents may need the gentle touch of one of the shaman to draw them from the places their bodies are laid. The spirit-filly hides behind Cirrus’ mane as they approach the bonfire - there’s so many there! So many tribes and the spirits the great song calls towards them. Laughter and tears mingled together, old friendships and loves allowed to end more cleanly and gently. But for the spirit of a foal, it can still be a frightening thing.

Until she hears it. One voice that doesn’t sing with the others. One that sends forth a different song, that the filly still remembers. A song that fades from Cirrus’ lips as she draws closer to the gathering. A song the spirit-filly tremulously joins as she approaches the mare that in life was her mother.