I'll respond to each of your questions individually. If I make an error, someone else can say what I messed up.
1. The fee that you have to pay Gallade is only if you use a custom Trainer Sprite. Otherwise, the card should be free. Also, any modifications made after you made the card (excluding change your moves when still in the 1st Bracket) will also require you to pay a fee.
2. The currency is indeed the Reborn currency, aka Rupees. You get them from either posting, asking for some from other members who are kind enough to give you some, or donating to the Reborn site.
3. There are no trainers. Just leaders. You have to beat at least two leaders to advance from the 1st Bracket, and it increases by three from from that point forward.
4. You have to be on the Reborn Server during the time when League runs, which Friday through Saturday from 4:30 PM - 7:30 PM EST. From there, you can ask how to challenge a leader and such.
There was a post actually regarding the whole system either in this thread or in the Hype thread. You must have missed it.