wifi extender question has been answered - it works fine to provide an ethernet jack to gear that must have it
re the lumin d2 vs bluesound node 2i... if you definitely don’t want more boxes (e.g., an outboard DAC to use with the node 2i), i would go lumin... it will sound better than the node 2i using its internal dac, and sound roughly as good as your ayre cdp
your system seems good enough you will definitely hear the difference between the d2 and 2i using their analog outputs into your ARC linestage
re the lumin d2 vs bluesound node 2i... if you definitely don’t want more boxes (e.g., an outboard DAC to use with the node 2i), i would go lumin... it will sound better than the node 2i using its internal dac, and sound roughly as good as your ayre cdp
your system seems good enough you will definitely hear the difference between the d2 and 2i using their analog outputs into your ARC linestage