Can I use Xbox One and Xbox Series S at the same time even if I'm not doing Gold/Game Pass...

Make sure you have the console your daughters are using set to your Home console. That allows you to share your games with your daughters so your account doesn't have to be signed in. https://beta.support.xbox.com/en-US/help/hardware-network/console/my-home-xbox Then
you can sign in and use your games on the other console.

HI there

There is a thing xbox do called game pass ultimate that has xbox live gold, game pass for xbox consoles and game pass for PC all in one subscription for £10.99 a month

Also if you set the xbox account as the home console on the Xbox series S then that console and the old console will be able to use the live at the same time without paying anything xtra.

Game Pass Core is just an online subscription, so if you purchase Game Pass for Xbox, you do not lose Game Pass Core, you will have both subscriptions at the same time. If you cancel Game Pass Core, then you will lose your Xbox One/Series X|S Games with Gold Games.

Do you mean an Xbox One S or an Xbox Series S? The game is not available for the One.

The game plays the same with or without Game Pass. You would just need Gold if you wanted to play online multiplayer.

If you are trying to do it on the same profile, then that is not possible. Profiles on Xbox One & Series X|S can only play games on one console at a time.

If you are trying to let someone else play your Game Pass games on a different console at the same time as you, then you need to make the console that you want to share the games on the Home Xbox using the account that has Game Pass, then anyone with a different profile can play those games at the same time as you.

Bear in mind the Home Xbox setting is only meant to be used in the same household, as using it with someone else not in your household can result in a suspension or ban.