So if I move everything out of electrum after fork, I will still be able to use those keys to be claimed on bch any time in future, is it right? even years later?
Yes. By this description your private keys before split contain the altcoin. I think you will always be able to redeem the bcc as long as it lives. Good for hodlers to know if in the future BCC becomes huge. I think it will die right away as I have not read any viable reasons why it will live.