I believe that NUMA nodes are all expected to be the same architecture.
This also sounds to me more like a CPU with additional commands than software that happens to run on another CPU (although with microcode, all CPU commands are 'just software running on another CPU'), think of it more like the features that some CPUs have to generate random numbers, or better yet, to do AES encryption in 'hardware', you create a memory area containing the info you want the command to run on, fill it with 'interesting' data, invoke the CPU command, and get back a large chunk of 'useful' data.