If your IP has to change, that's not a big deal. You can easily update any NS records and/or system configuration. Also, if it stays in the same DC, it's likely they could keep the same IP and move you to a different node.
Also, one of the key benefits of a VPS is the ability to move them from one host to another. This happens all the time.
What is the benefit of having 2 IPs?
Is there any redundancy in this VPS offering(since hardware/server is same.)? We would have to buy 2 of these dedicated servers with 1 IP each. correct?