You should always use static ports instead of dynamically assigning them. Where possible, disable the Browser service.

If you were to run the 3 instances on the same port and bound to 3 different IP addresses, Kerberos will not work. Each host is given a Kerberos ticket, not each name or NIC or IP. Your SPNs reflect the NetBIOS and FQDN names of the host, port and service.

I see no benefit to what you are trying to do. A better solution would be to separate your instances on dedicated ports. Specifying which IP Address your instance is bound to should be fine as long as your aware of your AD Domain and how Kerberos works.