OK, I’ll try to look into this and get a prototype working. I’ll post what I find as I find it so other people can use whatever I find if I don’t finish.
Looking at the Particle Xenon documentation it looks like the Xenons don’t support TCP outside of the mesh network, see TCPClient. So that makes sense that connect() doesn’t work when on the Xenons (but does work on the Argons).
So for me the next step is figuring out if Blynk supports UDP (which the Particle documentation claims the Xenons support) or finding out if the Particle Mesh nodes can be made to support TCP.