Airdrop is the only option available for now?
What about another bounty? will it available in near future?

If you look on WAVES DEX people are buying and selling SEGWIT using multiple pairs ie SEGWIT/BTC, SEGWIT/WAVES, SEGWIT/MERCURY etc

check it out

I've seen in waves dex and there is only one selling no one buy SEGWIT / BTC

Thats because the buys have been filled! SEGWIT is here to stay.

on DEX currently only buying not selling.