In surfing you put your controlling foot back. To find your controlling foot, ask your buddy to give you a shove forward. The foot you step forward on to stop yourself from falling is your controlling foot. This should feel natural. If the stance you choose doesn't feel right, just switch it.
Long leashes are for riding big waves and short leashes are for smaller waves.
A wetsuit will help protect you from the wind and cold water. How cold the water is will determine the style of wetsuit. For cold water you'll want a full wetsuit with arms and legs covered. A shorty has short sleeves and covers to the thighs like shorts. They do make women's wetsuits, which are much more comfortable than squeezing into a man's shape.