Need advice for my first build - part 2

Hi all,

I posted here before about an Xeon E3 build within $1,500 - $1,800 range. Then I thought it was better for me to go with an AMD Ryzen build. But then I realized AMD doesn't support Thunderbolt, which is an Intel proprietary technology. And that took my back to square one.

After doing more reading, listening to other Redditors' advice and reading other posts, I decided Xeon E5 might be a better build, considering PCIe lanes, using M.2 drive alongside x16 PCIe GPU, etc.

Now I have this current build, and I have a few questions:

PCPartPicker part list / Price breakdown by merchant

1. CPU: I'm debating whether I should get Xeon E5 2620 V4 or 1620 V4. The latter is is $100 cheaper with higher clock speed, but it's a quad-core CPU as opposed to 8 core. Thoughts?

2. Motherboard: Unfortunately, with this motherboard, using an M.2 drive will disable SATA3 4/5. I don't think it'll be an issue since I'll be using Thunderbolt 2 RAID storage for my projects. But out of curiosity, does this motherboard support Thunderbolt 3? I couldn't find that info.

3. Memory: Non-ECC vs ECC? 32GB ECC RAM is about $140 more expensive. Worth it for reliability/performance?

4. Video Card: Should I consider a Quadro card instead? For that price range, I'd be getting a 4GB card, instead of 8GB. Thoughts?

5. Thunderbolt 3 PCI Card: There is a Gigabyte Alpine Ridge Thunderbolt 3 PCIe Card, which is cheaper. Anyone has had experience with it?

6. Other Items: Should I consider alternatives to any of the other items on my list that could be more cost efficient or offer better performance?

This machine will be used for handling 4K+ RAW and H.264 footage using Adobe Media Encoder and Premiere Pro, and color grading/finishing in DaVinci Resolve.

Thanks!

UPDATE: For the curious and for those who are looking for similar builds, I ended up getting this build:

PCPartPicker part list / Price breakdown by merchant