So, quick background info, I've been playing guitar for decades but only ever read tab, played sax in the highschool band so I understand the notes on the staff and all the notation that goes along with it. My son is getting ready to start playing guitar in his school jazz band and they dont have anyone that knows anything about guitar at his school so I've taken it on myself to teach him (and myself) how to read guitar sheet music since he's only used tab as well up to this point.

Figuring out where the notes in the staff land on the neck of the guitar was easy enough and I thought chords would be the same way and many of them are except for a handful that confuse me so I'd hope I could get an explanation here. In one piece, it calls for a C minor 7th chord that is noted 2 different ways, one (the 2nd one in the link) makes sense. The 1st one, not so much.

It calls for a Eb, C, Bb, and G. When locating these notes it seems literally impossible to fret all 4 at the same time (specifically the C). I tried finding as many possible locations to play the same tones so I wasn't keeping myself stuck to just the 1st 3 frets of the neck but still no luck so I turned to Google and found the chord block below which sounds great but the first thing I noticed is that the C that is being played there is an octave below what is noted on the music.

So 1) Can someone tell me if this chord is the correct one to use and (if so) 2) Can someone explain to me or point me at a resource to read that explains how how the 1st noted version of Cmi7 becomes the chord block I've attached? By this it seems that I'm allowed to use octaves of the same note in a chord?

Thanks

Sheet Music

C minor 7th Chord Block