As Ethershift is supposed to rebrand to Switch.ag, will Ethershift tokens (ESH) remain the main tokens of the platform or there might be a swap to new tokens or something like that?
They will remain as main tokens of the platform as far as I know. On the new page Switch.ag you will even be able to see how much coins you get airdropped for your ESH. Quote from medium:
"Additionally there will be an entire page of the website dedicated to real time monitoring the volume and tracking the fees Ethershift has collected. This section will show when the next airdrop is, how much will be airdropped, and the approximate value per ESH you will receive. The first airdrop of the 50% of fees collected by Ethershift will be on March 31st."
EDIT:
https://medium.com/@ethershift/airdrop-wrapped-bitcoin-new-dex-more-bfb23beccca7