Hi, how do I claim my SBTC being stored offline on a Bitcoin core qt wallet ?
Also, I never claimed BTG, SBTC, BTX, etc. So how do I get them at the same time (I mean without missing the chance of receiving the unclaimed once being sweep) ?
Move your coins out of your core wallet to another wallet.
Open Core and dump your private key for that wallet.
Now use that private key to claim you coins.
As AvenG pointed out BTX is a little less clear cut, they have their own snapshots of the chain and you have to sign a message to receive and prove ownership of wallet. I believe this has come and gone and may be too late to claim unless they release more snapshots of the blockchain that qualifies for the fork coin.
From your dumped priv key you can use android app or ios to redeem your forked coins.
As you have moved your original coins to another wallet that wallet priv key is safe and if anyone tries to use your current priv key all they have is an empty BTC wallet.
Its important to move you coins when redeeming forked coins.
HTH