I can't tell you anything about the AVI Neutrons, but the Classik uses a connection known as a BFA connector (
http://www.british-audio.org.uk/connectors.htm). You can often buy these on eBay, or from somewhere like hifistore (
http://www.hifistore.co.uk/product.php?qsProd=CC124).
I've wound up getting 5 pairs with my Classik Movie Di and 5 with my AV5125, which means that I have all the connectors I need for biwiring, but I'm afraid I don't have any spare.
In terms of the speaker cable, I'd take a look at Van Damme (see various threads on here, do a search and you'll get a load of results). I'm using Van Damme 4x2.5mm black series to connect my AV5125 to my Linn Keilidhs, and it sounds very nice to me.
Good luck.
Rowland