what are the main requirements needed for planting a rose in a pot in India?

You seem to have gotten all the information you need. Just one thing I've got to add - roses' roots must never get hot, so paint the pot white or another light colour. Good luck!

Mm, I don't know much about this topic, but are rose bushes supposed to be planted in a vase? My grandmother had some roses in her backyard and they were pretty large plants... Maybe someone else knows.

Some type of roses blooming after just an year . And some of them are blooming earlier .

yeah sharm you know in summers the temperature is quite high in india, so the size is drastically reduced during summers, whereas you will get good blooms during winter, roses are plants that need much care, prune them by the end of september or in early october so they are ready to be bloomed by december and provide them with organic ferilizers, you can use cow dung, it will be help, my grandfather also used to nourish them with tea, ie left after making tea, i hope this will help