I have a Lumin X1 streamer with fibre. I would use the DAC's mentioned in the OPs choices with fibre converted to USB. I find it interesting that GTT (distributor of Mola Mola) used to demo the Tambaqui with an external streamer and not the built-in Ethernet streamer.
My long sold KRELL K-300i integrated (a great unit) had a built-in Ethernet streamer and it was not as good as using fibre converted to USB.
The built-in Ethernet is convenient, but my 3rd choice after fibre, USB, and then Ethernet.