I'am an aerospace engineer with 10 years of experience of in aircraft design industry. Your project is essentially a numerical analysis of the discrete data, and numerical differential methods should be applied. I will apply low-error (order of 2) differentiation methods for calculating the speed (by knowing the x and 7), and the rate-of-climb (by knowing the altitude). Regarding the heading, we have the x and y, and would not possible to calculate the "heading" (angle of body), but instead the "coarse" (angle of velocity) can be calculated.
I will give you a MATLAB code which will calculate these parameters from any sorted input, so you will be able to use it for future uses.
Also, I will comment on MATLAB codes, so you will understand it easily.
If you are interested, I can give you a sample.
Regards