Receiver and speaker set up for buisness

A receiver like this one
http/www.bestbuy.com/site/pioneer-700w-5-2-ch-4k-ultra-hd-and-3d-pass-through-a-v-home-theater-receiver-black/3548016.p?id=1219588129591&skuId=3548016&lsft=ref:212,loc:1&ksid=1e153f5b-9d7b-ac88-baad-000057005f34&ksprof_id=16&ksaffcode=pg2324&ksdevice=c&ref=212&loc=1&gclid=COqx4_GLzcsCFdgXgQodmjoOpw
can be used to power the speakers and has Pandora. You won't need the video stuff but stereo receivers don't usually have internet access. The 5 channels can be used to drive 5 speakers (set the surround mode to an all channel stereo setting) and you can set the levels in the area for each space.
You could also use a Sonos ConnectAmp to drive four speakers. This would allow access to Pandora and most any streaming services. Controlled by free apps for smart phones, tablets and computers it would also let you play nature sounds stored on a computer or nas drive.
With a Sonos ConnectAmp for each area you would be able to play different music or sound in each area and control them separately too.
More flexible but more expensive. You could start with one and add more ConnectAmps later.
Sonos can access the pay streaming service Calmradio which has nature sounds available as well as music.
If the Sonance Marriner speakers are within your budget I highly recommend them. Good sound and they last a long time. For inside you can get away with almost anything so save some money there. Pioneer or Elac small bookshelf speakers should be OK.