Ryzen X system for NAS, pfSense and some VMs

Hi,
I would like to set up my first ‘NAS & other stuff’ budget system. My requirements are:

  • NAS capacity around 8-10TB - buffered, mainly accessed from LAN
  • pfSense as VM
  • simple ubuntu server as VM
  • Plex for max 4 streams (3 inside a network and 1 outside’ish - VPN)
  • maybe 1 instance of some IoT server, i.e. Kaa platform

The important thing for me is possibility of future expansion for cheap.
I was wondering if you have some thoughts about my initial parts pick:

  • 3 x 4TB HGST for NAS
  • AM4 ATX B350 MB, i.e. Asus Prime B350-PLUS or ASRock AB350 Pro4 (both have 6 x SATA III and enough PCIs slots for Ethernet cards (pfSense) and 2 x basic GPU cards or SATA extensions and light overclock capabilities)
  • DDR4 EEC RAM (1 x 16GB 2667MHz) - whichever ECC model is compatible with CPU and MB
  • 650W EVGA PSU - I know it would be overkill at the beginning, but 10yr warranty and ECO mode (semi-passive cooling) when not in stress is good for NAS in my opinion
  • Ryzen 3 1200 with stock cooler and very light OC if necessary
  • some cheap ATX case with HDD cages

I would like to go with unRAID OS (USB 3.0 stick) and run Plex streaming and VM instancess from it.
For future upgrade I plan to go with more 4TB HDDs (8TG + 4TB parity as a start) and add them one by one - that is why I have chosen unRAID rather than freeNAS OS with ZFS.
In the future I would add 250GB SSD (either via SATA of NVME) for VMs and caching.
I would upgrade RAM with other 16GB sticks if necessary (up to 64GB) and also switch to another Ryzen CPU - 4C/8T, 6C/12T, 8C/16T - incrementally when necessary.
I would like to go headless for unRAID and pfsense. Maybe add some cheap GF 210 GPU or similar just in case.

I would like to know if my initial parts pick would be suitable for my requirements, especially Ryzen 3 1200, which is only 4C/4T CPU.

Thanks guys!