Hi Sam and welcome, now I can't answer your questions directly because I am not that familiar with the topic, the reason is pretty simple, I've never had the need to deal with that kind of stuff. But I can try to point in the desired direction. So, here is a pair of links that you might find interesting. The first one is a good starting point in my opinion, you'll find a lot of answers there. The second one is just a list of projects that use lwIP with a short description of the same.