I have my judgement for airdrop, first take a look how many airdrop (if too low I better skip it) and if you need to install a wallet, you can virus scan it first on web and this the important thing Install it on your virtual machine, you can backup it later after ICO and development ongoing as seen on roadmap since most of them just abandon project after ICO. About sending ETH to contract address it's normal since ERC20 token need gas (if you ethereum user you know what is gas for) and It can so costly if you have to sent bulk token for many address that's why they need small fee ETH to cover it.