You correctly decided to invest 1 thousand dollars in Bitcoin.
You can divide the remaining money into 10 parts for 50 dollars each and invest them in coins from the list of top 30 at the maximum capitalization. Look at the charts for how long in time they experienced the pumps and if for a long time, then boldly invest in them.

For me, binance is still the best exchange at the moment and is a favorite for traders because of the large trading volume every day and the existence of the IEO attracting investors. I think for now everyone will certainly agree that binance is the best exchange, with the presence of bnb tokens will make binance even better in the future

I don't think if ICO will make investors re-enter the market, because ICO has hurt the Crypto world, so when the price of Bitcoin goes up like it is now then the price of Altcoin is starting to plummet again, I think the rise this price of Bitcoin will make Bitcoin dominate the Crypto market price.

I don’t think that they will do IPO now. to conduct an IPO, they need to be very transparent and I think that they will not be able to open all the cards for an IPO.

Sending airdrop to your address may not create or permit anyone to steal your coins, moreover, airdrops are mostly sent in to Ethereum wallets not Bitcoin.
Just be extremely careful when trying to sign messages or make transactions .
Besides airdrops are worthless, they are mostly equivalent to few cents or dollars to the tokens or coins. So why take the risk just because you want to claim some tokens.