Hello itachi (did you miss the H at the beginning?)
1) New Delhi processing times are 25/26 working days, so lets say a month and a half, not necessarily 2-4 months but yes could be up to 60 working days depending on the paper work you submit and how straightforward the application is. And you can only apply for spouse visa from India, given that you are an Indian citizen. Even if you were to travel to the UK on a fiance visa to get married, I am pretty sure you will have to travel back to India to apply for spouse visa. And it is much much cheaper to get married in India and the food does not even compare!
2) Parents house is fine as long as she can prove there is enough space for one more resident to be accommodated in the house without it being overcrowded. A friend did not add this bit of evidence and had to run through council to get letters etc to submit later and it took over 6 months to get the visa. She should provide some utility bill that has her name on it too - gas, electricity, water, council tax, etc.
3) If your city of residence falls within New Delhi jurisdiction (North India), you will have to apply at New Delhi mate and not Bombay. Not sure why they are much faster!
Best option as I see it is get married in India, get all documentation ready, apply for spouse visa in India, get visa and then travel to the UK.
Good luck!