It isn't cultural appropriation to read someone's critical work. That's published work. It does seem a little weird to me that you aren't mentioning feminist literary critics in this post. It took about a minute of googling to find out that Gayatri Spivak has already written on colonialism and race in her feminist critiques of Jane Eyre. It's true that she's one of the most famous women of color writing about literature from a feminist and decolonialist perspective, nearly as famous as Audre Lourde--and she's actually written on the body of work you're writing about. A lot.

I guess what I'm saying is, no you shouldn't be applying critiques of intersectionality from political feminism to literary works, you should be reading critics who have already applied those critiques and engaging their arguments. Because otherwise the problem isn't that you're appropriating, it's that you're reinventing the wheel.