For 'Stealth' is Anita completely silent?
Well, yes. That's what silently means.

For 'Shadow Merge' is she disappearing and then teleporting? If so can she choose not to teleport? Also how far can she teleport maximum?
No? The ability does not say "teleport" it says "travel...for 30 seconds." It says nothing about teleportation, so no, it's not teleportation.

For 'Shadow Manipulation' do you have a guide for how strong a weapon she can create? If 'weak' iron is a good basic here.
Added. " A small weapon would be as strong as something between steel and whatever the next tier metal is." Remember that it is only good for one attack attempt, and that larger things are weaker.

For your 'Shadow Wings' it really depends on the other abilities you have and the answers to the questions. But flight in general is fairly flexible and you have particular needs to be met for them. So I'd say a minute maybe would be good, ten excellent. We can see what we have left after everything else.
Duration added. "This enables her to fly for up to 10 minutes "

I'm including poisons as abilities, unless you have purchased them in the past.

You're poisons etc are okay for now. Pretty much though they're as powerful really as we're going to every be able to make them I think.
Okay, so the poisons aren't on a sliding scale anymore anyway. They are what they are with no change in strength. When I wrote the effectiveness percentage in level 3 for Black Death and the healing potion, it was before I'd realized just how much one can do so long as they have a solid recipe. As long as the directions are correctly followed, just about anyone should be able to make a potion. The potions don't get stronger with character level because the recipe doesn't change.

They have never been purchased in a bazaar type thing because she makes them herself.

The potions listed here are merely what is memorized or being memorized. They are not the only poisons she knows. The whole point of the Apothecary's recipe book is to open it, find the potion best suited for the job, and make it. The books has 100s of recipes in it. If every poison is going to be its own ability, then we might need to scrap this, because the point of the recipe books is lots of potions at her disposal so long as she can procure the ingredients and follow the directions correctly.