Every project that has bounties or airdrops involved must expect some dumping from the people who get a free lunch. Nothing we can do about.
We could offer hold bonus or dividends. Masternodes also motivate people to hodl.
Don't think it would be possible to have masternodes on this project, but let wait for some expert advice from users.
Masternodes are a good feature to incentivize holding. But it also means some more centralization to the network. If done correctly the additional risk from centralization can usually be neglected.