Can I brought more than one package ?
If I bought exclusive access #3 for play and I’m waiting for discount to buy exclusive access #1 Can I do this ?
You can buy one of each DLC.
Yes you can.
https://forum.treeofsavior.com/search?q=Founder%20pack
Searching the forum or using search seems to be an extremely advance technique 
as for the questions:
YES
EDIT:NO my bad
there is nothing preventing player to buy 10$ pack 1st, play for a bit and wait for a sale (we know it will happen with 30% discount by the end of early access) and buy the rest 2 packs with a discount. The only downside of doing so is 3rd pack not offering token.
my bad, I misread it as getting a discount on the other packs after buying one of the packs…
lack of sleep sure hit hard…