I'm looking for Orange-Pi One hats with well supported Node-red integration for reading four 1wire buses with several sensors on each bus, drive two stepper motors, read at least 4 analog inputs (10 bit of higher) and read four 24vac inputs (a few outputs wouldn't hurt either).
The reason for the Orange-Pi one is that I already have one running Node-red nicely, it seems quick enough but I don't know yet what Raspberry-Pi hats are all compatible so I could also buy a Pi 2 or 3 if that makes finding hats easier/better.
Tindie has an interesting 1wire & analog input hat.
There isn't much support for physical hardware on the OrangePi boards in Node-RED
Even if you switched to a Raspberry Pi, unless the HATs are sourced from one manufacturer, there is a very big chance that they will conflict with which pins they want to use if you stack them.
Yes, the only real active support for Pi GPIO seems to come from the education area (Python, and Wiring, to a lesser extend Scratch).
For serious use, most people seem to use an attached Arduino (or similar) or a remote ESP. Mainly because if you mess up, you only have to replace a cheap microprocessor rather than the rather more expensive Pi. But also because you can easily expand the GPIO capabilities as well as offloading the realtime aspect of your code to a platform that is designed for it.
Well three of the hats I listed are i2c, some with selectable addresses so I thought stacking those should be fine but I haven't looked close enough to know whether the oPi One's pinout is 100% compatible.
I do have a modified firmata sketch on an Uno communicating with Node-red on the oPi. So far it can do the digital & analog io, and I've added onewire support by reporting the temperature readings via the firmata String support. I would just need to add support for the steppers in a similar way. I also have all the necessary hardware for the Arduino to interface with my project so that's what I'll probably use but I thought I should at least look at the option of doing it without the Arduino.
You might also consider your own code on the Arduino. I don't believe that Firmata has been updated in a long time and I don't think it is going anywhere.
Library support for Arduino is so good that even if you don't know C/C++ it is pretty easy to create custom code.
I have no problem coding for an Arduino but the purpose of this is to move an existing project to Node-Red on my oPi where I can host influxdb, grafana & mosquitto locally instead of relying on a dodgy internet connection.
One of the reasons for us using Node-RED is to avoid internet-facing services of uncertain security and longevity.