Here are some links for you that I think would be useful for a related setup, however I can't speak for the user that posted that. The headless installation should follow the same principles of using a RAMDisk though.
https://wiki.alpinelinux.org/wiki/Raspberry_Pi_-_Headless_In...
https://wiki.alpinelinux.org/wiki/Alpine_Linux_with_root_on_...