have a jvc stereo receiver rx-212bk and shopping for used speakers

Intention is to connect my technics sl-220 > jvc rx-212bk > sonos system. I already had the sonos and just got the other two pieces. I understand connecting to sonos is defeating the purpose of analog, but it is what it is. That said, I don't think my receiver has the output option to do connect to my sonos (?).

So, I'm looking at some used passive speakers on marketplace (zip: 68005) just in case I messed up when choosing this particular receiver.

I've read that two basic questions you need to answer to determine receiver-speaker goodness of fit are:

1. Does the amplifier provide enough power for my speakers?

2. Is the amplifier stable at the impedance of my speakers?

The speakers I found that are in my budget (under 100) are Technics SB-S407.

I'm not understanding how to answer those questions, though. Please help!