ĞBrazil would be another currency. It would indeed have its own UDs, different from the ones from Ğ1.
None is taken. But as we create more and more Ğ1s every day (in fact we create more exponentially) the value of 1 Ğ1 is eventually going to plummet. The more units there is, the less the value of one unit. At least when the population remains constant and many other parameters.
You were saying you wanted to make a website that would ensure the 1:1 rate between UDP and UD. This is what I was talking about. The thing is that you cannot store UDs. You can only store Ğ1s and over time 1 UD represents more and more Ğ1s. So if you offer UDs, you would have to give back more Ğ1s for 1 UD later - which you won’t have in stock.
Just to make sure everything is clear: when you create ĞBrazil, it will have its own independent blockchain, its own monetary tokens, its own WOT and its own life. A brand new currency. Completely out of the French Ğ1 ecosystem. Which doesn’t mean that we wouldn’t be able to exchange, after a while ĞBrazil and Ğ1 would certainly have some kind of rate of exchange.
Duniter is indeed a tool to create as many currencies as needed. But as it is still in its infancy, there is very scarce documentation about how to initiate a new currency - actually I don’t even know if there is one at all. On the other hand, you have to understand that this is totally new software so everything is possible, including major bugs.
The “1” stands for “first” Libre Currency. The Ğ stands for intangible values (that’s a very short explanation - more here http://www.glibre.org/fondement-semantique-de-ḡ/
It is the current number of members. There are more users, although it would be quite hard to determine the exact number.
It was a metaphor to show that Duniter is an UFO in the world of crypto. 
At least that’s how I understood it. 
There is a funny anecdote about Pizza Day on this forum: Etrillum restaurant en monnaie libre Ğ1 - #57 by jeanferreira