TiggerJen - I hope this response isn't too late for you!
I also have lipo-lymphedema, and I completely understand your anxiety.
Personal experiences - most times, I've found that most people have been friendly, helpful, and not rude. Most times. But there are always those ignorant few... Try not to let those get to you if it happens.
Getting the second seat is great - It's especially nice that SW changed its policy and you now get refunded for the second seat. Although it's somewhat an inconvenience to have to pay for it up front, I can understand; I'm sure that making it a bit more difficult means they don't have people just claiming the need when they don't really need the extra space.
First thing - you will get a seating group. I haven't flown SW since all the policies changed, so I don't know if you will be put in the first group if you have two seats or not. Regardless, check with the agent at the gate and let them know you have purchased a second seat. You will get a "reserved" sign to put on your second seat so the FAs know not to count that seat as open, and so others know not to sit there. I know that most of the time people won't try to take an open middle seat next to a "pooh-sized" flyer, but that just makes it easier. Don't be afraid to ask to do the "early boarding" if you need to. That may be automatic with the extra seat - you have to be able to get on while you can find adjacent seats, obviously. But be proactive and make sure you get on early so you don't have an issue.
Even with the extra seat, be prepared - if you do really need the second seat, it probably won't be comfortable. The ridges of the seats can be painful after a while, especially with the lipidema. I often take a seat cushion with me to make it a little easier to deal with. A blanket or a jacket over the raised armrest can help too.
As far as the seatbelt extender - I simply let one of the FAs greeting people as they board know that I need it. They will either hand it to me immediately, or they bring it to me when they are doing the final flight check. There have been a few times the FA has forgotten - if they are doing the final check (making sure seat backs are uprights, tray tables are up, and seat belts are fastened) and I don't have it yet, I flag one as they are passing and let them know I asked for an extender and don't have it yet. All this can be fairly discrete, but if you have to remind them and a seat mate is going to hear, don't let that stop you. Your safety is too important to let a little embarrassment get in the way.
One other thing - getting to the gate in the airport can require quite a bit of walking. I still walk it - though sometimes it gets a little tough, but I learned years ago to do these things to make the airport easier:
- check luggage: don't drag a whole bunch around the airport. What may seem like "not much" becomes horrible to deal with when you are trying to walk to the gate that seems miles away!
- For any carry-ons: take something that rolls. Again, I've made the mistake in the past of thinking, "this laptop bag isn't that heavy; it's just a MacBook Air, an adapter, and a few other small things." That was before I knew about the lipedema. Carrying something like that through the airports gave me so much pain I could barely move later.
- Give yourself plenty of time. Murphy's law says that if you get there early, the security line will be short and a breeze; get there late, and it will take forever. I like giving myself plenty of time because it reduces my anxiety greatly, and that way, if I have to stand a long time in the security line, I can sit somewhere and rest a minute before I continue to the gate. I can take breaks on the way if I need to. And I always make sure to use the restroom just before boarding.
Hope this helps a little!
