The duration of this route is above proposed time, since only the time for via feratas would be s.th around 6 hours. Also please note, the path with sac scale T0 corresponds to Tajakante via ferrata with difficulty up to D/E.
The topo of all three via ferratas can be found here:
https://www.bergsteigen.com/fileadmin/userdaten/import/topos/tajakante_klettersteig_topo.jpg
The duration of this route should be around 10-11 hours:
1.0 hour(s) - reaching the first interesting part
1.5 hour(s) - Seeben via ferrata
1.0 hour(s) - between Seeben and Tajakante
3.5 hour(s) - Tajakante via ferrata
0.5 hour(s) - between Tajakante and Coburger
0.5 hour(s) - Coburger via ferrata
2.5 hour(s) - descend back to the car