We had an Escape wedding a year ago - October 29th! I won't be able to answer quite everything, as we used the wedding pavilion, but I'll answer what I can.
"Can you pick your planner":
I believe the answer is no. You will just get assigned one. If you have problems with your planner, it is possible to get switched. I remember back when I was planning my wedding that a few other people had that problem, complained, and did get a switch. But generally, I don't think they let you pick for that. Also, I know in our case, our planner got switched out on us at the last minute - I think it was within the last 2 - 3 weeks before the wedding. Our original planner got moved to custom weddings, and we were given a new planner. I actually found out here on the boards that I would be getting a new planner at least a week or so before Disney ever let me know.
All that being said... don't worry about it. It's an area where Disney does its job well. I've seen very few people have problems with their planners. And I think, from what I've seen, those that have, Disney does try to get it resolved quickly. As long as the planner you get is responsive to your questions, is doing what he/she is supposed to do... things should go well. Even though we got switched at the last minute, everything went extremely smoothly. My mom commented several times on how amazed she was at how well organized Disney seemed to have it all.
"Using the provided photographer or booking their own?":
We booked an outside photographer. The options and costs on the packages from Disney photography have changed now, so I don't know for sure if our decision would have been the same. Originally, we wanted to use Disney photography for everything, figuring it would be easier to let them do it all. The deciding factor for us was the cost of getting the digital images. We were going to end up having to pay for extra hours of photography, and then an additional $750 to get the cd with all the digital images. And we were going to get prints and an album we could have cared less about. We tried to negotiate with them to get them to keep all the prints and the album and just give us the digital images instead, but they wouldn't, and wouldn't even give us any kind of discount on the digital images.
We found for only slightly more than that, we could get 6 hours of photography with an outside photographer that included all of the digital images. So, in the end, to get what we wanted, it was cheaper to go with someone outside.
In hindsight, it's probably what we would have wanted anyway. We decided to do a moving photo shoot after the wedding where we got shots at GF, in front of Epcot, at the monorail, on the ferry, in front of MK, at the Poly, and at WL. I doubt we could have done that with Disney photographers.
"Recommendations for outside photographers?":
We used Misty Miotto, and I can't say enough good things about her. You can check out some of her work at mistymiotto.com. I have only gotten a very few of the over 1000 shots she took up on my web site, but you can see a few from our wedding at kims-world.net. Just navigate down to the wedding page, and look for the professional wedding shots.
Another name you'll see a lot on the site is Randy Chapman. He was the other photographer we were considering - it was basically between him and Misty for us. It was just a personal decision on style and what packages they offered that made us decide on Misty, but we would have happily taken Randy as well, based on his website, on the wedding pictures that others have posted on here that he took, and on the wonderful things anyone on here who used him has to say about him.
If you do go with Disney photography (and I've seen examples that show there are some really good Disney photographers as well), search the boards to get info about the different experiences, and to ask people about the different photographers. And don't be afraid to request a specific photographer or photographers. Or to say you don't want one in particular. We had a VERY bad experience with our MK portrait shoot. But many people's turned out beautifully. There are others who also had bad experiences, and it seems at least a few of them had the same photographer as we did. But others have had this photographer and loved him. So.... you just have to judge for yourself what you want.
"Recommendations on hair?" - When you actually get your date for your wedding and get access to your planning website, part of what's on there is a set of resources. There is a list of recommended providers for hair and makeup. Almost all, if not all of them, will do the early hours for the MKPS, for an extra fee. They come to your hotel room. I used anna at makeovermajic.com, and I was very pleased with the results. Again, people on the boards all have their favorites, and if you do a search, you'll get a number of different names.
"Will the planner help with any post/celebration gathering...?":
The answer on that is very mixed. Some have had good luck getting the planner to help out. For most, the answer is no - they seem to just give you a few ideas about where you can go, and the rest is up to you. Anything more, and they really expect you to be doing a custom wedding. I didn't try to do a Magical Gathering, and don't recall seeing people doing Escape weddings talking about that, so you might have more luck with that. But generally, you have to do any of this yourself, unless you are adding on one of the "sanctioned" add-on events, like a desert party or something. And most people doing an Escape wedding don't, because the cost of that for that small of a number of people is worse (per person) than doing it for a larger number.
All of this is either my experience or what I remember of other people posting. Things may have changed some since last year though, so maybe others will step in and correct some of this or add to it.
Also, you may still want to work with the restaurant manager on things like personalized menus.
