Here's something interesting about that old hag's deals that might help you plan ahead. Making deals with auntie ethel in the beginning really shapes how things play out later on especially in the final act of the story. If you keep her alive she shows up again at the blushing mermaid, disguised as captain grizzly and you can actually bargain with her for some pretty decent rewards like a permanent ability boost from her hair.

You might think killing her early is the way to go but funny enough, she comes back anyway through some weird magic. The main difference is you can't really negotiate with her anymore which closes off some interesting opportunities. Now about that eye deal she offers, it's definitely tempting but remember, you'll be stuck with permanent disadvantage on perception checks and say goodbye to those sweet critical hits. Plus mayrina just disappears from the story completely.

Speaking of mayrina, saving her actually opens up some cool story moments later on when you find her with these hag survivors. You get to see how she's dealing with everything including stuff about her husband connor being brought back to life which is pretty interesting. The cool thing is that no matter what you decided about ethel earlier, you'll still get to deal with that whole situation about vanra and the kid she swallowed trying to make a new hag. Its just that your options for handling it might look a bit different depending on your previous choices.