In Banjo Tooie can Banjo have a green pterodactyl or dragon in his back pack instead of Kazooie?

I think I know what you mean here. There's an upgrade for Kazooie called Dragon Kazooie, which you get by finding the Mega Glowbo and taking it to Humba. But you can't have anything in the backpack other than Kazooie, in either of her forms.