It is stated in Rambam Isurei Biah - Chapter 15 - Halacha 25:
When an asufi is found in a city inhabited by gentiles, whether the majority are gentiles or the majority are Jews, the child is considered as gentile of indefinite status with regard to his lineage. If he consecrates a woman, she needs a bill of divorce because of the doubt. If someone kills him, he is not executed for doing so.
My question is, if this person ended up marrying a Jewess of non-doubtful status, is the child a safek asufim? Is a safek asufim a sfake sfaka and permitted to marry into the kehila?
And also in the related Gemara (final perek Kiddushin), it lists several indications where the asufi would be considered kosher (i.e., if he had milah already, etc.). If someone had a relative three or four generations removed and such details have been obscured, would this also be a sfake sfaka?