Heartly Congrats Mr.Arjun M.K For Passing IPCC in first attempt.
Its a Dream Come true for everyone.
My answers for your questions are as follows
1.Dont register for Ca final Now itself,as there is an advantage.Its,Change of Study texts,concepts such inclusion or exclusions may happen.When your Final attempt is 2.5 years later,There might be changes to occur.so be patitent and register before Oneyear of your attempt.So that u get Upto Date Books and refer Directly.
Also appear for Interviews,Build good Knowledge.
2.Join Classes before 1.5years of Final attempt.Although its better to join now,but take a break..Learn Plenty things in articles,cos once you join classes you might be confused shuffling between Audits and Classes..so it may become Uneasy.
Its always better to study final syllabus,any point of time.
3&4.Doing articles has both advantages and also DisAdvantages.Advantages are Knowledge,Exposure,Learning in vast areas,serving big clients,paypackages..and etc.Disadvantages are You get loess time to manage tutuons,FewLeaves,and they wont listen to your personal issues as in Mid size firms CA's understand and permit us specially for Classes etc..
Login to their sites,look at careers..Its even better if there are any BigFour places known to you..Visit them,meet Persons working,get to know directly about openings.Importantly Recomendation plays keyrole in BigFour.
5.Visit your Icai chapter,Get info there.bcoz i cant answer this.
Note-Its just my opinion out of knowledge i have,Its always better to have your own opinion.