Text of the ordinance:
German: https://www.admin.ch/opc/de/official.../2016/2577.pdf
French: https://www.admin.ch/opc/fr/official.../2016/2577.pdf
Italian: https://www.admin.ch/opc/it/official.../2016/2577.pdf
It is an interesting and convoluted case. The following answers are based on the new law.
No. Sonnebrand IS eligible for facilitated naturalization after three years of marriage and 5 year of stay based on Art. 21 Abs. 1 and Art. 21 Abs. 3. Lit. b as his wife became Swiss because of decent from a Swiss mother.
The rule with fewer years in case the spouse became Swiss after marriage the regular way seems to no longer exist in the new law.
As it is facilitated residency requirements by canton and commune do not apply.
If it were a registered partnership it would be regular naturalization and the residency requirements by canton and commune would apply. Based on Art. 18 it could be up to 5 years in the commune.
As it is facilitated permit C is not needed. Permit C is only needed for regular naturalization.
Either regular or facilitated. There is no middle ground.
Correct.