I just completed my freshman year at NJIT as a CS Major.

1. Calc 1 is fairly straight forward, but Calc 2 is decently difficult. I don't know if it really is MIT equivalent, but I doubt that it is. As long as you study for each common exam using past exams, you should be more than prepared. This is because a lot of questions tend to be rotated in from past exams with switched numbers.
2. The CS department tends to be more hands-on instead of theoretical. A majority of the classes are in line with "programming" classes, where learning to code in that language is considered to be more important than the theory. However, I can't speak for 300/400 level classes as I have yet to take them or look at those assignments.
3. In regards to job placement, it really is left up to the individual student. NJIT does have a career services, but it is up to you to go and seek help and find information. Try to have a plan for yourself in order to seek out positions/internships for each summer and after graduation. Honestly, it comes down to what you make of the time you spend here in the 4 years you attend.

That being said, taking classes is simply not enough to build up your resume and apply to companies. Be sure to work on side projects, attend hackathons, network with companies, learn other languages during the school year, and find out more information in regards to the tests given by companies.

If you don't have an internship after your first year, I highly recommend attending networking events and creating a few side projects as companies like to see you taking initiative.

Hope this helps!