Bounty restrictions can fix few problems facing project price drop after listed on exchange,
1) if any dev want to avoid dumpers then they must limit bounty participants, the limit the participants they better ,if a bounty only request 300 participants at highest and the 300 became a dumper it won't hurt ,unlike 2000+ participants
2) devs should forget bounty when still on ICO ,allow bounties after your project finished ICO successfully and make your project is doing great before allowing bounty
This are just ideas ,if you have anything better please drop on here and let's share.
The truth is none of your options can work with crypto currency bounties because you do not understand the basic function of bounty program.
THere is a need for high volume of participants in bounty programs to enhance the global coverage of the project on all social media platforms and its entity.
Secondly, how can a project make sales on icos when there are no publicity ??
Basic solution is to increase the number and levl of tokens offered to bounty programs, that would give them value for work done, because bounty hunters dump when they end up receiving 100, 200, 50, 30 tokens