Can I have a second username for my paper trading account?

Each IBKR account is only allowed one paper trading account. If you have multiple IBKR accounts, each one can have its own paper trading account.

To open a second paper trading account:…

No, it is not possible to transfer positions into a paper account, even for informational purposes. In order to establish a position in a paper account, you must place a trade from within the paper trading account. …

To enable market data for a second username, it is necessary to log in to Client Portal with that username to request live market data…

ADD A USER

With linked accounts you can not designate a default account for login purposes. If you want to login to a specific account then you would need to create an additional username for that account…