Your questions are so broad that it is hard to offer you any advice. However, we can direct you to some resources that might be helpful to you.
To get a better understanding of the electrical components that you plan to use, I recommend reading the articles on our "Engage Your Brain" blog about servos and LEDs. You might start with reading the "Understanding battery capacity - Ah is no A" blog.
To get started with wearable electronics, the Wearables page on the Adafruit website contains various guides, which might give you insight to what devices you would need for your project and how to build it.