Please read the following two questions given in the 57 FAQs issued by the Institute this month which is relevant to your case
"Q31: What will be our attempt if our first group is already passed and registered in articleship in March 2017.
Ans: In Nov. 2017, you can appear in IPCC Group-II (provided you have registered for Group-II or both Groups uptil 30th June 2017) under the existing scheme for the available attempts.
Q30: I’m currently pursuing articleship and in 1st/2nd year of training. I have not yet registered for Final course. Do I compulsorily need to register for Final Course before 30th June, 2017 in order to continue under existing scheme.
Ans: Yes. Only the students registered under the existing scheme till 30th June 2017 will be able to pursue the course as per existing scheme, thereafter they will have register under the revised scheme only."
Now in your case:
1. How long will take depends upon case to case and the time cannot be quantified. So please have patience and wait till the revalidation letter comes.
2. Yes as per above questions old course shall be applicable to you.
3. As it is apparent by reading Q.31 yes you can give your second group in November 2017 under the old course.