1. If the price is right, absolutely. It's a quality tablet with sufficient horsepower inside. if you like the features and form-factor, sure. My daily driver laptop is the same generation and a little bit more powerful than the Pro 2 and its perfectly fine. Heck, even the Pro 1 will be fine. These gadgets have largely been getting more efficient, not necessarily more powerful lately.
2. If the battery isn't in good shape, absolutely not. It's nigh impossible to repair and attempting it will likely result in serious damage to the glass, display, etc. This will only become more of an issue going forward but it probably isn't a huge worry yet.
3. If you're planning on keeping it for an extended period of time, such as beyond a few years, probably not. Go for something that's either newer or less disposable/easier to repair than the Surface series. But as a secondary device or toy to play with, knock yourself out.