The reason for the Pi 4 is because there are issues with the Pi 3 b+ and earlier models using only 1 Bus lane for all networking traffic. So the ethernet/internet, all usb ports etc shared only 1 bus lane which created bottlenecks. So the miners wouldn't run up to full speed and some would simply crash and the miner would stop working.
The Pi 4 has multiple bus lanes so there is no longer that bottleneck many of us experienced before. And with you having so many miners I would highly recommend the Pi 4 over any of the prior Pi models. And the 2gb Ram models will work fine as a controller. I am using a Pi 4 with 2gb of ram to control my 2 R606's, 4 Newpacs and 2 futurebit moonlanders without any issues.
I have a 4gb Pi version that I just tinker with and often use as a desktop replacement.
**edited**
As for the script, the miner works with both newpac and R606. Here is the script setup that I run with my newpac and R606s combined:
In the above example I'm using them to mine Litecoin Cash. I would suggest breaking this out into two separate mining windows for the newpac and r606 since you are adding the other miners as well. Until you are fully stable. Just so if you have to make tweaks to the frequency of the R606's you don't have to drop the newpacs and so on. So some of the miners are still running / connected. I have mine all in one miner as I've already tweaked and have it set where I want it.
Once you have your Pi 4's, I recommend using the NOOBs flavor of their operating system. It's just easier/quicker to get configured. And once up and running you can run the following commands to get your Pi setup where you can remote desktop into it from any windows pc or laptop.
First you will want to set the Pi to boot to login screen instead of straight into desktop. Click on your raspberry start menu at top left, go to preferences and then Pi Configuration. This is a very lite gui version of the main config. On the first tab you should see boot to desktop as Pi or something similar and it's checked. Just uncheck it. Ok or Apply and then open a console and do the following:
sudo systemctl enable xrdp
sudo reboot
Then you can just remote desktop into your Pi's IP address. And you will also want to change your Raspberry Pi's machine name if you are going to run more than 1 on your home network. As sometimes they will clash. I ran into that issue as I had my mining pi, pi-hole server (that one is a 3 b+) and my tinker one all with the same host name To change them do the following:
- option 2 - Network Options
- N1 - Host Name
Then select finish when you are done changing the host name then reboot the Pi.