Vellore

I don't think they have categorized the hostels based on seniority.
Refer to the URL below, you will get the complete idea about hostel blocks and rooms available there.
A-4AC, 4NAC, 2NAC and 6NAC
B-3AC and 3NAC
C-2NAC and 4NAC
D-1AC and 1NAC
D Annex-3AC, 3NAC, 4AC, 4NAC
E-2AC and 2NAC
F-2AC, 2NAC, 6AC, 6NAC
G-1AC, 1NAC, 4AC, 4NAC
H and J-1AC, 1NAC and 3NAC, 6NAC (new)
K-4AC, 4NAC, 6AC and 6NAC

It's pretty decent. 26 students from that branch got 10 LPA offer last year.

Yes, there are good chances with above 90%.

You'll get the withdrawal link here:
vit.ac.in

Vit.ac.in is the website where you'll get the withdrawal link.

Yes, there is a good chance.

For Vellore CSE, it's 5K. For Chennai, it is 12K.

VIT-Vellore any day as it has better placements and infrastructure.

It's a very new course, so no comments.