I would like to assign multiple IP addresses via DHCP on the same interface. Does the DHCP protocol and DHCP servers allowing this?
If the DHCP Client IDs are set to different values then you should be able to statically allocate different addresses. I say "should" because it's rarely done and support is sparse.
Your use case is at least partly accounted for by the spec (RFC-2131) in that a server must use the Client ID for identification if one was provided by the client.
You might try dnsmasq. According to the dnsmasq FAQ (about halfway down), it treats duplicate MAC addresses with differing Client IDs as different devices.
On the client, you can set the Client ID with dhclient's ``-I [Client-ID]'' flag.
No, DHCP only provides mechanisms for assigning a single IP to any one MAC address.