Hello,
If you want a chance to buy limited pin on september 14th, you'll have to install the Lineberty application on your phone . ( For Iphone :
Lineberty For android :
https://play.google.com/store/apps/details?id=com.lineberty&hl=fr )
When you open the app, you will have a list of places that use Lineberty (airport, stores ...) so you will have to find Disneyland Paris. You will see the lines you can join for DLP wich includes Meet & greets and shows. Those lines are geolocated, you have to be in the park to join, BUT NOT THE PIN TRADING QUEUES. You can join those lines from anywhere, the only requirement isan internet connection.
The one that you are interested in is "Parc Disneyland" > "Pin trading". As you can see, there is 2 pin trading lines: Pin trading and Last chance.
Pin Trading queue is opened
2 days before the day of the sale at 18h (6pm) : so this thursday . If you manage to get a ticket for that one, you'll be sure to be able to buy 2 of each limited pin. Your ticket is numbered and give you an appointment to respect. You can be late but be sure to be at the Pueblo Trading post before the start of the Last Chance Queue (14H / 2pm for this saturday).
The last chance queue is opened
1 day before the day of the sale at 18h (6pm): so this friday . It's the queue to have a chance to buy what's remain. The ticket is numbered and when the last chance start (14H / 2pm for this saturday) they start calling in number order so you have to be at the pueblo at the start of this call. When this queue start, all the Pin Trading queue ticket are canceled so be sure to come at your appointment if you have a pin trading queue ticket. The last chance can buy 2 a each limited pin as long as the pin is available. It does not guarantee to buy any so it's all luck/popularity based.
You can redeem a last chance ticket only if you don't have a regular pin trading ticket. You can get only one ticket from those queue on each device (yep, multiple device works but be sure each device has internet in the park: park free wifi, 4g/3g ...).
If you don't have the chance to get a ticket, trade table are installed oustide the Pueblo so you can trade with people who bought the limited pin.
I hope it's clear even with my english mistakes, feel free to ask me anything. My advice : test the app with random queue from random stores to see how it works.
EDIT> i forgot to mention that even after the last chance queue, some pin can remain, it almost always happened after à best friend release, except when it was Ariel or very popular character. I've been doing the linberty war since the very beginning and i can predict this week it's an easy one. And i'm pretty sure that pin will remain after the last chance queue.