I have a btc wallet that received Bitcoin Cash in the 2017 hard fork.
That's not really what happened. It was not an "airdrop". In simple terms, Bitcoin Cash duplicated the existing Bitcoin block chain at the time. So, for all the Bitcoin addresses you control, you also control the equivalent Bitcoin Cash addresses and the BCH they might contain.
If I sweep the private key into my Electrum Bitcoin wallet, do the BCH, Bitcoin SV and other airdrops remain attached to the private key?
Nothing you do with Bitcoin affects Bitcoin Cash, Bitcoin SV, or any of the many other forks.