Muse as the actual muses-wise, I’d say that
Maki is Eutrope (music),
Rin is Urania (astronomy, Hoshizora),
Hanayo is Clio (history -> history of idols)
Umi is Calliope (epic poetry – songwriter)
Honoka is Thalia (comedy),
Kotori is Polyhymnia (sacred poetry, fits her pure image.)
Eli is Terpsichore (dance obvs),
Nico is Melpomene (tragedy)
Nozomi is Erato (love/erotic poetry, ie Snow Halation).
Relatable FE Quote or Something 