Will a colt junior 25 acp pocket pistol magazine or one for an astra cub work in an fie the best 25 acp pocket pistol?

No, a Colt Junior .25 ACP or an Astra Cub magazine will not work in an FIE .25 ACP pocket pistol. Each of these firearms has unique magazine designs and specifications, meaning they are not interchangeable. Always use the correct magazine designed specifically for your firearm model to ensure proper function and safety.