Most dutch and north-west german are undishtingable from swedes if we substract the baltid influence in sweden imo. So they can pass for non baltid/baltid influenced swedes all the way. Most southern germans might be a different story though. I doubt a somali or even a mena might be goodamm swede, no matter how many generations they are living in sweden. Physical appearence also has to do a lot in regards of integration and self-identification with the new country you choose to live in.