Hey,
Here are some suggestions for you:
1-What do I teach? Simplified or traditional chinese?
I would suggest Simplified Chinese because it is commonly used in China and it is easier.
2-Am I able to teach my daughter mandarin when I dont speak it myself??
You can expose her child to Chinese native speaker such as getting a Chinese nanny or get educational materials online or from stores. Chinese children songs will be good as she will pick up easily with the music.
3-What if I am pronouncing it wrong??
This is a good tool of Chinese text to speech. As much as you want to teach her, you can learn as well.
http://www.iflylanguage.com/ltt/