The sim card you get, will have a different number, but it is possible to get your old number transferred on to it.
You should be able to get a sim card from an EE shop (if you have one nearby, as this might be the easiest option) plus if my memory serves me correctly, they should be able to do the number transfer for you.
If you are wanting to basically use pay as you go without a pack. You can do this, but you must do the below, before you put any money/top up on to it. Again, if you get the sim card from an EE shop, you could mention this to them, and they should be able to do this for you. But otherwise, this is how you use a top up without a pack:
You need to text STOP PACK to 150 before you first top up.
After you have done this, and you topped up for example £10, this would put this £10 into you pay as you go balance and any calls/texts will be deducted from this money balance.
I will point out that you would need to make a chargeable text or call before 179 days from your last one, as otherwise your sim card would go into hibernation. So providing you do this, you can top up as and when you need to.
Not sure on the data part, but something makes me think that I've read on here that you don't get access to data, when you don't have a top up without a pack. But I'm not 100 percent sure on this.
If you did purchase a pack (for data) and then later wanted to go pack to topping up as and when needed, and without a pack, you would need to do the STOP PACK part again, BEFORE you topped up, and this would stop the credit going on a pack.
Hope this helps 🙂
