I have few questions, hope someone can answer them for me...
1) When i open an image in SPP, it doesn't resemble the in camera JPEG. How do i achieve that?
The in-camera JPG is created by a specialized chip in the camera, so sometimes it's a bit hard to get your output image to look like it.
I think the closest way is to use the Neutral color mode, and Auto WB. If the colors still seem a bit off try adding +0.3 saturation in SPP.
2) When i cook an image in SPP, it loses all the changes once i close the program. Is there anyway i can change this behaviour. Can i save presets (pre cooked settings like LR) in SPP?
You can save settings into each file (the "Save X3F" button, or checking "save settings to X3F" when you export).
Also you can save adjustment settings as a preset to apply to multiple images - in the adjustment settings panel there should be a button to save presets. Note that previously some settings, like noise reduction, would not be saved into these presets - not sure if that is still true.
3) Monochrome: I am yet to play with this. Those of you who have used this mode, is there any advantage of using this over channel-mixer in Photoshop? How should they be any different?
The Monochrome mode is a totally different raw processing pipeline than the color one.
Using the channel-mixer in Photoshop only gives you results as good as the color conversion. Using SPP Monochrome you can get sharper results at higher ISO, and also possibly smoother tonal transitions. It also better approximates the application of color filters since it's mixing the results of data captured at each layer rather than on the final color the image has after combining layers.