Here are the answers:
1. No, not necessary. If you are getting into some other company for indutrial training, it should meet criteria as specified. Also, a separate form will need to be filled and sent to ICAI for their formalities.
Details: https://www.icai.org/new_post.H T M L?post_id=784
Form: Refer the forms under 'Industrial training' https://www.icai.org/new_post.H T M L?post_id=721
2. Min tenure is 9 months and max is 12 months. You can appear for final exams only when who have completed 2.5 years of articleship. There is provisional admission for final exams in such cases.
Also, period of exam holidays and exams are also counted for articleship (subject to leaves allowed by ICAI). The remaining portion can be completed after final exams.
Hope this helps. All the best!
Regards,
Rahul