I’d encourage you to hire a professional, rather than taking random help from someone on the internet. They’d likely be able to give you quicker answers to your questions, and you’d have a recourse if the information is either incorrect or misunderstood.
That being said, there’s Sonos Amp is designed to power a stereo set of speakers, or sometime two pairs, if both sets are of the correct impedance. You might potentially go with some sort of impedance correcting volume controls, depending on your situation. The Sonos Amp can control three pairs of Sonance Architectural series speakers, which are specifically designed for such use.
For the one speaker at the front desk, I’d suggest an Sonos Era 100 speaker.