what do you think of players of certain aspects having traits of others? Like, a Light player that is very interested in knowing themself, and loves to roleplay/make characters

People are more nuanced than simply being tied to a single Aspect, even with something that stands out. You could also parse a lot of things relating to other Aspects through the lens of your main Aspect with enough introspection for sure. Whichever the case, it can happen, specially with your complementary Aspect.