It is up to uscis and then the embassy as to whether they issue the certificate of citizenship and then B visa.
”
FAM 402.2-4(B)(7) (U) Children Seeking Expeditious Naturalization under INA 322
(CT:VISA-1826; 09-06-2023)
a. (U) Naturalization under INA 322 is a permissible activity in B-2 status. You may issue a B-2 visa to an eligible foreign-born child to facilitate that child's expeditious naturalization pursuant to INA 322. The child must be under the age of 18 when INA 322 requirements are met. The child's intended naturalization, however, does not exempt the child from INA 214(b); the child must intend to return to a residence abroad after naturalization. A child whose parents are residing abroad will generally overcome the presumption of intended immigration, if the parents do not intend to resume residing in the United States, whereas a child whose parents habitually reside in the United States will not.”
If they have determined that you live abroad and qualify, I don’t know what the mechanism would be to deprive your children of citizenship.
The good thing is your son just turned 17. Apply now to Holtsville field office. That is a 1.5 hours on train and 5 minutes Uber from jfk airport.
They say on the website that processing is 6.5 months. Perfect. That takes you to Christmas holidays. Get your certs, go back to Germany.
Return after 2025 school year.
If this fails, you will find out soon enough to start i130. I would still try DCF with job offer from your cousin.
Your son is under 21, so no quota.