Perspective system advise needed.

You don’t need a DAC for Genelec the ones speakers. The new KEF LS60 would work in a small room, again no DAC or streamer needed. Dutch and Dutch 8c another with built in DAC and streaming if using Roon.  I've never heard the A500 but I have tried the A700, you should consider their hub so you have access to their room correction.  Don't know about the Focus 30 but Dynaudio is coming out with a new active you can stream right to the speakers. Devialet Phantoms ditto no DAC or streamer needed. Of these I like the Dutch and Dutch then Genelec 8351b. 

Still, my impression of a Terminator II and Terminator Plus is that these would give me a much more refined and life-like sound compared to the built-in DAC in my NODE streamer or most of the wireless speakers you have mentioned.

The speakers I mentioned don't have to be ran wireless you can connect them with ethernet cables. I agree with your FutureFi minimalism which is why I pointed out  the speakers you were looking at you don't need a DAC, more to the point using an external DAC would not change the sound as all of the inputs go through the built in DAC of these types of speakers. The analog input simply goes through an ADC first so while it is possible to use your own DAC it doesn't do anything except add another conversion and increase cost. 

I think you're on the right track with your philosophy but do a bit more research on the speakers you're considering.  The Genelec 8351b is an excellent speaker and in a small room I doubt a subwoofer would be needed for most music. 

You don’t need to go down the rabbit hole of DACs it’s one of the least important components in a system unless it's a distortion generator. You definitely don’t need to watch YouTube videos from PS Audio. The active speakers you’ve mentioned all have good DACs in them, there are some that don’t  have DACs but you haven’t shown any interest. If you are interested, Focal Trio11 be, Neumann 420, Geithain 804 are some good ones. I have heard a lot of these speakers and for the money the Genelec 8351b or KEF LS60 and Buchardt are exceptional, depends on your preferences. Don’t get sidetracked your thinking is spot on.