In the Hunter x Hunter manga, the focus isn't on whether Gon smells or not. The story is more about the adventures and character development. So, the answer is no, there's no such aspect depicted.
A really interesting plot could be set in an alternate universe where Gon and Kurapika have different roles. For example, Kurapika could be a carefree adventurer like Gon usually is, and Gon could be more focused on revenge like Kurapika. This role - reversal would create a whole new dynamic between them and could lead to some really unique storylines.
In fanfiction, their relationship can be deepened if they exchange stories about their pasts. Gon could tell Kurapika more about his father, and Kurapika could open up about his clan. This would create a more intimate connection between them.
To create a sense of fear effectively, the author should focus on the character's reactions. If Gon and the OC are in a scary situation, show how their bodies respond, like 'Gon's hands trembled slightly as he reached for his fishing rod, his eyes wide with apprehension.' This makes the readers feel what the characters are feeling. Additionally, unexpected twists and turns can heighten fear. Just when the OC thinks they are safe, something even more terrifying could happen, like a supposed ally turning out to be an enemy in disguise.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.