I have two wallets in the oasis wallet, one of which is with Ledger, can I transfer my ROSE that I have delegated to the ledger wallet without removing them from staking from the other wallet?
If you want to send your ROSE from one account to another, it is mandatory to undelegate. Tokens delegated are locked with the signature of one public key. You cannot transfer this signature while Coins are locked. Remember the unbounding period is 14 days. The validator takes its commission from your rewards when they are distributed. This happens every epoch (approx. 1 hour)
The total amount you see in your wallet includes auto-compounded rewards. At that time, the Validator already got their commission.