That quote literally says "you can respec them anyway".
It's referring to the fact that by the time they're in your party proper, you don't get to pick their subclass normally.
This refers to Wyll, who is a fiend warlock, and Shadowheart, who is a trickery cleric, this is because their origins involve those subclasses.
Once they are in your party you can respec them.
So yes, TC, you can make her a different kind of cleric, and honestly there's more options that can work with Shar than that cannot.
Just avoid Light and Life.
