MCA

M.Sc IT itself is equivalent to MCA but MCA students are more preferred by the industry.

College change or university change after the first year is completely dependent on the college and university norms, some universities allow it and some won't plus you need to have good scores in the first year to apply for the same. For further details contact the college authorities.

Yes, it plays a vital role in the selection of students and in many aspects it is important. But, it is not the only way to enter CU students can also enroll themselves directly through the online admission process.

Both are good in their respective fields. If you want to continue your further studies in computer science and application, then MCA is the best option. But if you prefer going for corporate and business sector, then MBA is your best option.

The basic requirement to do a PhD is a Masters degree, so you automatically qualify since you have a MCA degree. To apply for Ph.D. you can either directly apply to the professors of
different universities sending them your resume , Statement of purpose
and your research papers. Or you can appear for UGC-NET examination
and then sending your NET scores to the professors under whom you want
to undergo your Ph.D. course.

Best Books for MCA Entrance Exam
IIT-JAM (MCA & Biotechnology ) Previous. & Practice Papers (Solved)
by
Editorialrph Board
Publisher: Ramesh Publishing House (2011)
Mca Master Of Computer Application Entrance Exam
by
R. Gupta
Publisher: Ramesh Publishing House (2008)
MCA Master of Computer Applications Entrance Exam
by
R. Gupta
Publisher: Ramesh Publishing House-delhi (2012)
TANCET MCA (Anna University) by V.V.K Subburaj
By
G. K. Publications Pvt. Ltd
MCA Entrance Of All India Universities
by
G.K.P.
Publisher: G. K. Publications Pvt. Ltd
The Pearson Guide to MCA Entrance Examinations
by
Edgar Thorpe, Showick Thorpe
Publisher: Pearson Education

Dear Ankit,
Yes, you can go for MCA from University of Mumbai.
Below are the links for your help.
http://mu.ac.in/portal/distance-open-learning/distance-open-learning-more-info/
https://www.shiksha.com/college/institute-of-distance-and-open-learning-university-of-mumbai-santacruz-east-10303
I hope this will help you in the best way. Feel free to raise more queries or you may close the question by liking it or marking it.
All the best.