8 SATA ports - yes it has 8
Onboard diagnostics code - Yes
Onboard power/reset buttons - Yes
Intel nic - 2 Intel Nics
3 full sized pcie slots and 3 mini pcie slots - No it has 4 PCIe 3.0 x16, 1 PCIe 2.0 x1
M.2 must not be placed next to GPU, it must not disable SATA ports if used. - 3 x m.2 and 2 are placed next to PCIe x16 lanes.
Fully featured not gimped bios - Check
Capable of 3200CL14 ram in all 4 dimm slots. Board vendors struggling with this, often only 2 primary slots capable, just catering to the max 16gig ram crowd. - Check but 4 dimms is only half populated but will run at 3466 cl16 or 3200cl14.
At least one usb type c port, but not too many as currently all my devices type a usb. - 1 Type-A + 1 Type-C
Front usb 2 (and of course type A usb 3 headers) headers still need to be present for my case. - USB 2 & 3 at front of case
DVI or VGA output present on outputs if I get an APU. - No apu's on x399