There are two types of digital connections possible between player and receiver. One is an optical connection (TOSLink), the other is a coaxial connection (SPDIF). You know what a TOSLink cable looks like. The coaxial digital cable is just a regular interconnect with RCA plugs at either end. The outputs and inputs where you plug in the "double (R and L) cable" are ANALOG, not digital.
Lets start at the CD or DVD disk itself. The information on the disk is digital (1s and 0s). Your speakers, however, are analog. So, somewhere between the disk and the speakers, the digital information must be converted into analog information.
If your player has both digital and analog outputs, then the player has DACs (D
igital to A
onverters. Actually I don't know if there is only one or if there's more, but regardless, the player has something, DAC(s), that convert the digital signal to an analog signal).
But your receiver ALSO has DAC(s) that can do the same job. If you hooked up the player to the receiver with a digital connection the the information on the disk stays in the digital domain until it gets to the receiver. If you use the analog connection between player and receiver, then the player converts the digital info into analog. In order to take advantage of the digital processing in your receiver (DD, DTS, etc.), the receiver must receive a digital signal. If you send the receiver ONLY an analog signal, all you're gonna get is stereo.
As this wire table
will show you 14 gauge wire is just fine for just about everything except a cable run of over 40 feet to a 4 ohm speaker. Most of us use 12 gauge just to be on the safe side. No big deal.
Don't quite understand your subwoofer problem, but if you connect the sub to the "sub" or "LFE" output of your receiver, and properly calibrate all your speakers, your sub should be balanced with the 22s just fine.
I'm not an expert, so anybody that feels I haven't quite presented this correctly, please correct me.