But she'll be making the wrong decision.
I don't care what reasons she has for doing 6 A-levels. The point is, it is pointless.
If she is doing those subjects because of her interest in those subjects, but not English Lit, sorry, but she can expect a Cambridge rejection.
Especially considering the fact the OP
asks what ECs she should do to convey her passion.
Tbh, I find the OP very arrogant of her abilities, and you seem to be a bit on the defensive side on her.
It's not just me who is saying this you know. What about the other people on this thread who AGREE with me.
If she wants to take 6, and she does not get that A in English Lit, let's put it this way, she took a decision, and therefore suffer the consequences of it.
You say "what if she gets 6 As". I say "what if she gets a B in English Lit".
Anyways, 6As is hardly an achievement.