we are using ICMP protocol as a primary polling to get data from your IP addresses. If we can detect just "some device" behind IP address but no SNMP protocol enabled, then we just show USED but no additional data.
If you want to collect device details using SNMP to scan your network subnets, complete the following steps:
a. Check Enable SNMP Scanning in the SNMP Scanning section.
b. Provide an appropriate number of SNMP Retries.
c. Designate the SNMP Timeout for SNMP requests on your network. The timeout value is measured in milliseconds.
d. Enable SNMP neighbor scanning.
Also, if you are showing data from DHCP server (DHCP scope) you should be able to see MAC address all the time.
Regarding IP address conflict - this is something we are currently working on post IPAM 3.1.1 and beta will be out soon.