Not yet, for either.
Finoha is currently English only, and has one theme — the dark one. We would rather ship a single language and a single theme that are properly done than a settings screen full of switches that half-work.
Both are on the list. If a particular language would make the difference for you, tell us at info@finoha.net — we do count the requests, and it genuinely affects the order we build them in.