According to https://www.kotus.fi/kielitieto/nimisto/henkilonnimet/etu-_j... the standard for same gender is 5 people that are alive, i.e. once 5 men and 5 women have that name, it could be given to either gender. Not sure what would happen if there was a huge imbalance though (like 1000 women with the name & 10 men). At least Rauni and Kaino have been granted to both genders after the law came in effect.
For example, there's such rejected first names as "Marihuana", "Avicii", "Kapteeni" (Captain), "Salaisuus" (Secret), "Noppa" (Dice), "Hoito Virhe" ("Medicial Malpractice" as first and last name) and "Sukka" (Sock). Guess the idea that giving a boy a girl's name can have a similar effect for the child as naming them "Sock".
Hade to look that up. He apparently named his son "X Æ A-12": https://www.bbc.com/news/world-us-canada-52557291 . Will probably create some issues with future IT-systems. I know a "Jo Å" and he have trouble registering for services from time to time.