The i3 6th gen is perfect for you
I would get the unit, 8GB of memory, and an Intel 600p SSD and run with that.
This message was posted on behalf of Intel Corporation
There are many Intel® NUC Kits you can get to install Linux as main operating system but please bear in mind the Intel support team does not provide suggestions this type of inquiries.
I would recommend checking the list of NUC's that support Linux:
Supported Operating Systems for Intel® NUC Products
You can see some customer operating system experience with Linux:
Also, try this link to compare Intel® NUC Kits.