Do link skills work with assists like Dance?

Pretty sure they don't. Has to be something like Reposition, Swap, Smite, Draw Back, etc.

They do not work with sing/dance, as the skill says "When a movement assist skill ... is used by unit or targets unit,..." Sing/dance are not movement assist skills, so they do not work.

If you want to buff your teammates and dance them at the same time, you could try using the specific dance skills (Geyser Dance, Torrent Dance, etc) and also use their seal versions.