Responses from crn3371

Best DAC for around $2,500 or less
I’m fond of my Wyred 4 Sound DAC. Truth be told, at this price point you’re opening the door to many excellent units. A lot will depend on your listening preferences and synergy with the rest of your components. 
Streaming from Bluesound Node2i
That’s basically the Node’s only function. Experiment with your connections, I prefer coax over optical. If you go with coax make sure you’re using a true 75 ohm coax cable, not a standard rca cable. 
Tablet for Streaming
Buy a streamer. Use the tablet for remote control.  
Aurender A10 + Burson + Modded Sonos Connect = Need Help
Have you contacted W4S? 
With that budget, a streamer. 
Bluesound NODE 2i Wireless Music Streamer and kef LS50 W
Bluesound NODE 2i Wireless Music Streamer and kef LS50 W
Yes. Analog via RCA, digital via optical. I’d try both ways, see which DAC sounds best. 
Waht is the best streamer for the money under $2500 (no DAC or storage required).
What seems to be getting lost in this Teac argument is that the OP is asking for a Streamer without a DAC. The Teac is a DAC that also streams, not exactly what the OP is asking for.  
Any one else using DIRAC or silimalr for 2 channel set uo?
I’m using ARC Genesis with my Anthem STR integrated amp and quite happy with the results.  
Non Analytical Sounding DAC Upgrade- Budget $1,500 or less
I’d recommend contacting Wyred 4 Sound. They have some new old stock options available that don’t show on their website. I picked up a DAC2DSD-SE that was within your budget.  
Can we talk streamers based on UI rather then SQ?
If you don’t want to use Roon for $ reasons, and can use a pc as your streamer, I would recommend looking at Audirvana. 
streaming source
I have both mainly for variety and selection, but if I had to choose only one it would be Qobuz. I generally prefer the sound of Qobuz hi-res over Tidal MQA. 
streaming source
No clear winner. As tvad said, get a trial of each and decide for yourself. I’ll leave the whole MQA argument to the others. 
Can we talk streamers based on UI rather then SQ?
If you’re not happy with BlueOS you most likely not going to like the other player specific apps. Your best bet is to find something that can operate as a Roon endpoint. 
Want to get into Streaming
What are your goals? Budget? What existing equipment do you currently have?