If you look at the packet capture from the eero router that is successful and the packet capture from the ISR1111 that is unsuccessful, the major differences seem to be options  60,61, and 124.   There are also differences in option 55(parameters requested), but most of those are not allowed by the IOS-XE 17.9.4a command set. 

With how the IOS-XE DHCP client sends the DHCP Discover message currently (or with default config, or any config I have tried) I get no response from the ISP DHCP Server. 

My goal is to have the enterprise grade Cisco IOS-XE mimic the eero in what is commonly referred to as mac-cloning, but the ISP seems to be extra finicky..