Great article Jeremie !
Regarding the airdrop, to be more specific, the rate of 7.316% applies for the first 12 months after the token sale (until December 2018). In 2019, the monthly rate will be 2.11637%, and finally 0.88187% for 2020.
For being eligible to the monthly airdrop, no need to have participated in the initial token sale, all you need to do is to buy the token on an exchange, and then just make sure that your PXS is in an address which you own your private key (MEW, Metamask) on the last second of the previous month.
For example for the June airdrop, the snapshot of your tokens held we will be taken on 31st May 23:59. Hence you may freely move your PXS at other times through out the month.
Last but not least, these airdrops (or "unlock of tokens" as PundiX like to call it) are calculated monthly, hence it is a compounding process from the first time you start holding PXS.