Can the applicant choose the city where he will be appearing before the notary?
Through the platforme of request of the citizenship (Spanish citizenship request at Justice Ministry) the applicant will only be abble choose the city for appearing before the notary, but he will not be abble to choose the notary.
In the case of an application for a family group, the platform allows the group to appear before the same notary.

How much will the notary fees cost in Spain ? 
We do not know the final price because it depends on the number of pages of the notarial act.
But when the applicant will receive the invitation to attend the appointment, he could ask the detail budget of his file.
I’ve already signed the Afficavit more than 12 months ago and I do not have any answer of the Ministry of Justice. What happened to my application?
Applications to get the spanish nationality ruled by this law have to be resolved within twelve months from the reception of the application in the General Directorate for Registries and Public Notaries (Affidavit + documents) with the reports issues by corresponding entities of the Ministry of the Interior and the Ministry of the Presidency.