Medicine

Private medical colleges, after filling up their ranked seats, tend to work on a basis of marks+first come first serve basis. This allows admission for people with unfortunately low grades. I hope you'll get admission in your desired private college.

600 marks may get you a seat in state quota but not from AIQ, at least for government colleges. But many private colleges do have subsidized seats for the ones who score good but didn't get into any government colleges.

Divide your topics into the one you are sure of, the ones you need to revise, and then ones you need to learn again. The first category just revise once in every three days. The second, once every day. The third should be solidified. Keep arranging your topics accordingly.

Any college for MBBS is more or less the same, it's just the reputation. It is recommended that NCERT should be followed only for NEET as it is sufficient to get you a good college. Don't indulge in other material that make even the simpler things go above your head.

GMCH Chandigarh, being on the rise, has seen its cutoff go from 1k to now 350 ranks and above for general category.
The state quota for GMCH Chandigarh is now even more prestigious due to the stern eligibility rules. Students scoring above 570 have been given seats in MBBS via state quota.

It depends on your scoring and preferences. Government aided colleges are much cheaper than private colleges. AIIMS gives you admission in under 10,000, other government colleges require not much higher, whereas private colleges seek more than INR 50 Lacs in the entire course of MBBS.

Offline tests are important in a way that it gives you a feel of OMR sheet filling. There have been many cases where marks have been lost due to improper OMR filling, so practice of filling these sheets is necessary, atleast from 1 month before the examination.

400 marks in NEET are less for getting government Medical College using All India quota. As the All India quota cut off usually goes above 500 to get admission in government medical college. But you can get admission in private Medical Colleges easily using your NEET score
But you can try some good private medical college.

You'll get know about it in college campus through placements or you can also try off campus placements. There are many posts in AIIMS after B.Pharma.

Well, Your marks are not enough for admission in B.Pharma through the cutoffs but if some colleges conduct spot admission by interview sessions you must try. And non the less you can always go for the private institutions for a guaranteed seat.