So, first off, if you “have the sheet that the cards came with” and that’s actually sheets plural, not sheet, they might actually be their citizenship certificates, if indeed they became citizens after the switch to the citizenship certificate. If you have their actual certificates, you can apply for the passports for the two children who don’t have them. Here is a picture of what one looks like.
However, if the sheet singular and it is just the commemoration, then you will have to apply for new citizenship certificates for the child without either, before you apply for the passports. A citizenship certificate application can take quite a while.