I noticed the XXV710 is part of the Fontville series, which includes the X710 and XL710. Additionally the NVM package is the same for all 3 of these NICs.
https://ark.intel.com/products/121745/Intel-Ethernet-Controller-XXV710-AM2 Intel® Ethernet Controller XXV710-AM2 Product Specifications
Is it possible to flash the 4-port 10GE X710, or the 1-port 40GE XL710 to function as a XXV710? Even if it can only support 2x25G connections, it would be fine.