I don't know your situation, but is it possible that the original T2 diagnosis was incorrect? Type 2s don't "become" type 1s. They are two different conditions. In most cases, T1 is an autoimmune disease - the immune system attacks the insulin-making cells in the pancreas. I believe that the onset in adults can happen more slowly than it does in children, which is why many adults are misdiagnosed as T2 when they are really T1 (at least, that's what I see a lot of on this site!) You would need c-peptide screening and antibody testing to know for sure. Your doctor may have already done this, but check. If you're taking insulin, your treatment won't change, but with an "official" T1 diagnosis, it can be easier to get approval for things like pumps and CGMs.
Regarding your questions:
1. Research all the available pump models before deciding which one to get. Take your time and do your research carefully, because it's a 5-year commitment. You want a pump that has the features YOU need/will find most useful.
2. Read Pumping Insulin by John Walsh. Make sure to get the 2012 edition that just came out.
3. A "continuous glucose monitor" is a device that provides near-constant measuring of blood sugar levels. Some people do find CGMs very helpful. Dexcom makes what is probably the most popular CGM, and they just released a new model. I think people have the most success with this. Minimed also makes a CGM that is integrated into their Revel pump. Most people would agree that the Dexcom is more accurate. Some like the Minimed CGM because it means you don't have to carry around as many devices.
4. t:slim is the newest pump on the market. It definitely looks great, but I would be hesitant going for it as a first-time pump user unless you feel really comfortable trouble-shooting and dealing with issues. Personally, I would stick with one of the tried & true pumps (Animas Ping or Minimed Revel).
5. I personally use the Revel pump and love it. It is very durable, has a proven track record, has the integrated CGM, and has all the features that I need. I do a lot of outdoor activities and needed a pump that was durable and wasn't going to break in the middle of nowhere. Thus far, my Minimed has met and exceeded my expectations. However, you may find that the Ping is more appropriate if you're around water a lot, as it's the only truly waterproof pump.
5. The Minimed and Ping have some key differences. This is a great video that highlights some of the key differences: http://www.youtube.com/watch?v=2M0KeIqdYro
Take your time and do your research carefully. Watch videos on YouTube that show people using their pumps so you can get comfortable with how they work.
Agreed with what all MyBustedPancreas had to say. Pumping is very individualized and you have to pick a pump that works best for you. Some people really find being tubeless a BIG priority. Omnipod is currently the only device that is tubeless, but it just didn't appeal to me for many reasons. I too would be a little leary of tslim at this point. I mean it LOOKS wonderful, but there are some issues that concern me, and make me want to hold off for a bit on making that decision. Durability, and also the battery issue. It's rechargeable like an iPhone is from what I've read...but how long does the battery life last once charged, and how long does it charge for. With my good ole AAA battery. I can just pop a new one in at anytime, anyplace, anywhere and keep going.
I also use Minimed Revel pump. I have been pumping for a year now and it really has made a big difference, BUT it is also a lot of work and dedication to testing and testing frequently. It is definately in my opinion more flexible in a lot of ways, but also that flexibility comes with a price, as only having rapid acting insulin in your body, if there is some problem with an infusion set or a pump malfunction, you are getting NO insulin and blood glucose levels can very quickly start rising and it can be easier going into DKA because of that. That is why frequent testing is just that much more necessary on a pump. Frequent testing can catch problems quickly before they become dangerous. While Medtronic really does have a very good track record, and in the year I've been pumping I've had zero problems with it, all pumps still are electronic devices that can fail.
You have good options and probably can't go wrong with any of them.
The Tslim user group reports good things about the pump itself but some people report delays in ordering and receiving it through insurance (I guess because Tandem is so new).
Another pump option is the Accu-Chek Spirit Combo which has a full-featured remote similar to the Animas Ping.
I love my Dexcom. If I were you, I would consider getting set up on CGM first as it is an invaluable tool when starting on pump. There is a real learning curve to CGM and pump and you may want to tackle them separately.