1. The gas giant will lose mass, and eventually be destroyed. But it might take a really, really, long time. So long, it's unlikely that you'll see anything happening. We're still working on tweaking that portion of the code.
2. We've talked about simulating magnetic fields, and Dan seems keen on the idea. Other then that, we don't have anything specific planned yet.
3. The gasses will be stripped, but right now they're not directly linked with the atmosphere. We are working towards having this work a lot better.