Nintendo published Mario & Sonic at the Olympic Games in Japan, so no this isn't a "new practice" for Nintendo. They probably did that game in Japan due to owning Mario as an IP.
As for Capcom and Monster Hunter, maybe Capcom originally said they were going to release it and then backed out, and Nintendo stepped in and said they would take the publishing risks. Who knows. Capcom has released plenty of games in Europe, so it shouldn't be a problem for them either.