Hi,
I think the Hair Tool developer is open to uma support, he mentions uma in his release notes.
I am working on hair tool uma integration that I am planing to share.
The integration requires a scalp slot to be a separate renderer and it Instantiates a hair prefab when a compatible renderer and wardrobe item is active.
I use a custom GeometryProviderBase to handle uma’s blend-shape baking.
Here is WIP example of using uma’s blend-shape baking.
I really like the hair tool so far, but I have not had time to work on anything but the technical stuff.