Thank you guys for such a fast and comprehensive response. This community is great.
So this I think I should do please correct me if I'm wrong
Regarding BTC
1. Since I have my old keys in old Multibit Classic Wallet download legacy Multibit Classic Wallet export PK to Electrum as shown
on this video
https://youtu.be/LaijbTcxsv82. Generate cold storage PK for BTC in legacy format using bitaddress.org (of course offline) or in new segwit format using
Segwitaddress.org (is this site legit and reliable PK generator
?)
3. Transfer BTC from old address to new cold storage address in Electrum
Regarding BCH
4 .Same as point 1
5 . Generate cold storage PK for BTC in legacy format using bitaddress.org (of course offline)
6. Transfer BTC from old address to new cold storage address in Electron Cash
Thank You guys in advance for reply