Hey,
As for route one, if they do have one, then well and good. But keep in mind that this industry, just like any other, is a volatile and dynamic one; everything keeps changing and since you are talking about a 5 yr timeline, it would be utterly foolish to presume that things will stay the same for the next year or so, let alone for the next 5 years. But nevertheless, if they do have one, doesn't matter if it's Indigo or KF or 9W, if you are an Indian national, this is the best route imho, if you sincerely want to work in India. But keep in mind that you will be enslaved -read bonded- to that airline for, God knows how many years, and you may feel helpless during that course of time. In US, as of now, you can only work your a$$ off as an instructor once you are done with CPL as there are virtually no airline jobs for an inexperienced, immigrant driver. This is based on my personal experience.
As for the self-sponsored CPL mentioned in your second and third routes, that would make sense if you are planning, or you are willing, to work anywhere and everywhere on this planet. Basically, it would make you flexible enough as you would not enslave yourself to a particular airline or to a particular region. I have no idea about the MCC/JOC course which you mentioned but as for the ATP, you won't get it in a fortnight, at least not in the US. Here, you need at least 1500 hrs, coupled with some other minor req., before you can appear for the check. Also, route three would work if you have sufficient Vitamin J -read Jugaad- and/or Vitamin W -read Waasta- in India
AFAIK, the only foreign airlines which used to hire/hire outsiders, as Cadet Pilots, were/are SQ and CX (albeit their website now states preference would be given to HKID holders). EK, EY and GF have their own too but it's reserved for the locals. But hey, since you are looking at 5-6 yrs down the line, you never know!! Just stay abreast with all the happenings and even if things don't go well, apne dil pe haath rakh ke boliyo, aaaaaaaaaaaaaaal is well
