We do suppport FabricPath with Nexus 7K/5K/6K product line. Both N7K and 77K supports Fabricpath with F-Series line cards and will continue to do so. The same support will continue on Nexus5K/6K switches. Fabricpath as a technology feature is part of the Cisco Unified Architecture and has a great roadmap.
Nexus9K does not support FabricPath as the hardware is designed on Merchant silicon and the ASIC's do not support FabricPath encap/decap on the line-cards . Nexus9K is all together built-in on an ACI architecture to provide the fully integrated and automated network fabric solution driven by Application Network Profile.
We do support vPC and other Layer 2/3 features to integrate the system with Nexus Products in NX-OS mode. This should work seamlessly. The NX-OS on N9K is an enhanced NX-OS which will provide you with better performance on N9K hardware.