Yes, it is possible to add systems with static IP addresses to PiHole DNS automatically.
Yes, it is possible to add systems with static IP addresses to PiHole DNS automatically.
Yes, it is possible for PiHole to automatically add your servers and printers using static IP addresses to its DNS.
It hasn't been long since I relied on PiHole. Isn't there a device directory that checks PiHole for DNS queries? It shouldn't matter whether the devices have static IPs or are using DHCP.