Sonos Connect directly into MC452?

I think it would be a good combination as long as you do not expect to stream at higher levels than CD Red Book (which is all Tidal offers right now, and I guess in the near future). Tests of Sonos players have been very favourable, and these days volume control in the digital domain is not an issue. If you are still worried about that, you could add a Level Pilot volume control.
Alternatively if you wanto add a convenient streaming option for higher resolutions (from a NAS), you may want to consider the Chromecast Audio, into a high quality DAC.

It will work just fine and let you listen to music until you decide what, or if you want to upgrade.

+1, mattmiller

With the exception of LAWNMOWER comment 😉

The Connect needs a good DAC to fully justify the pairing with MC452. To my ears, the sound from its analog output is lean towards dull and flat. 

Lean and flat is often an other way of saying accurate. However, if the OP really wants to be sure, why not get a Benchmark DAC3?

@willemj 

What so special about Benchmark DAC3 vs any other sub $2K DAC?