There is not even need for a bifurcated driver. The upstream kernel has AF_XDP which Intel and Mellanox NICs support in their drivers, and DPDK has official integration for it as well: https://doc.dpdk.org/guides/nics/af_xdp.html This will make deploying DPDK significantly easier for those that need/want to use it and allows to share the same driver for pushing packets up to DPDK and into the normal kernel stack with very close to "native" (as in user space driver) DPDK performance (target is ~90-95%).
The old classic BPF is still used by seccomp, but in the kernel transparently converted into eBPF. In the kernel we dropped the notion of eBPF and just call everything BPF (as the old classic BPF is pretty much a thing of the past and not extended / developed any further).
I'm not sure where you have heard about this? Their DCTCP extensions have never been posted in the first place to a public list as of today. Pretty much all of the core TCP developers for the (upstream) kernel's networking subsystem are employed by Google and doing an excellent job. That said, I would love to see their extensions integrated into the upstream tcp_dctcp module.