10 webhooks but only 4 subscriptions?

Troubleshooting
6

Are you expecting to catch your own events or the respective webhook responses?

The hook-response/ filter will only catch the latter ones.
If you want to test the former, you need to prefix your event names with ... well ... a fix term like

  Particle.subscribe("number_", myHandler, MY_DEVICES);
  Particle.publish("number_one", data, PRIVATE);

BTW, I'd rather avoid String and go with

  char data[32] = "getting data";

And all these delays will also impact responsiveness of the cloud task as in these cases the cloud keeping only happens once per second - instead of aprox. 1000 times with non-blocking programming techniques.

About the ESOCKETTIMEOUT have a read here