Shirayuki may be able to use a sword/knife as needed in combat but Meguru is someone who has had to live on the battlefield known as a soccer stadium. He has to dodge fast hits and move like lightning. He has every physical advantage over Shirayuki and is just more experienced in combat. She will not be able to defeat him with her current abilities and only after a lot of training would she possibly stand a chance. Meguru Bachira wins.
Shirayuki may not be trained as a fighter all that much yet but she is used to surviving out in the wild and foraging for materials. She has a lot more actual field experience compared to Fern and that’s going to work to her advantage. Fern’s detective stories just don’t substitute for real world experience. It won’t be enough to shake up the outcome of the fight here. Shirayuki wins.