I normally see some crypto projects which promise Investors certain amount of dividend depending on how much coin/token they own.
The word "Investors" is normally used for people who own shares of a particular project/company, but in cryptocurrency this "shares" normally refers to coins/tokens, which makes me wonder if bounty/airdrop hunters are also considered "Investors" since they hold certain quantity of these coins/token
Yes, of course, they are also investors because as you said they hold part of the token even if they do not use funds to acquire these coins, or even if it is a gift as long as you have these coins you are an investors and you have the right to sell or hold it as long as you like.