I understand BCC/BCH is similar to lumen (but 1:1 ratio based airdrop). [
BCC/BCH is just an altcoin is being created with air drop plans based on snap shot of blockchain as of August 1st 2017 12:20 UTC.
It's not though.
BCH keeps the entire Bitcoin transaction history and simply diverges from the Bitcoin blockchain by introducing blocks with a different ruleset after the 12:20 UTC. This is exactly the definition of a fork. A BCH full node will be able to verify the entire transaction history from Satoshi's Genesis block to the present. The ruleset it will check will change from time to time, including a change after 12:20 UTC on August 1st.
Why big hype on BCC/BCH and how they will survive 51% attack ?
There's nothing preventing a large Bitcoin miner from 51% attacking BCH. It'll cost them a considerable amount of money in lost mining income, so I guess that's what the BCH folks are banking on.