1) If you come before 1st Oct, you will be considered as resident. total salary will be taken for tax calculation in India. House rent, school fees etc can be claimed if payment is made in India not otherwise.
2)If your period of stay is less than 182 days, foreign income will not be taxed in India.
3) You can keep NRE account for upto 3 years.
4)Interest is tax free, till you are non resident.