01.2 When must the application for initial accreditation be submitted to the Accreditation Council? Is retroactive accreditation also possible here?

According to § 26 para. 1 sentence 1 MRVO, retroactive accreditation is possible for initial accreditations. Specifically, this means

Accreditation is valid retroactively from the beginning of the semester or trimester in which the Accreditation Council made the accreditation decision in accordance with § 26 para. 1 sentence 1 MRVO.
Examples:

• One study programme will be accredited for the first time on 15.09.2019.
  The accreditation period runs from 01.04.2019.
• One study programme will be accredited for the first time on 10.12.2019.
  The accreditation period runs from 01.10.2019.
• A higher education institution will be system accredited for the first time on 15.09.2019.
  The accreditation period runs from 01.04.2019.
• A higher education institution will be system accredited for the first time on 10.12.2019.
  The accreditation period runs from 01.10.2019.

(In these examples, it is assumed that the winter semester runs from October 1 to March 31 and the summer semester from April 1 to September 30. These deadlines change accordingly if the semester runs differently).

However, higher education institutions must comply with the applicable state law. The host country may require a successfully completed accreditation for the start of study operations. In this case, an application for program accreditation of a study programme that has not yet been opened at the time of the inspection must be submitted in good time so that the decision of the Accreditation Council can be made before the start of the study programme. Details must be clarified with the responsible ministry. Due to the different requirements under state law, applications for initial accreditation are also given priority by the Accreditation Council.

You can submit an application in ELIAS here.