Yard boss set coupler issues

[Dragos]

I just bought the yard boss set at hobby lobby over the weekend. The caboose will not couple together regardless of the way I put it on the track. I have to left the car up slide the couplers together and then set the wheels on the track. I have to do the reverse when I put the train away. So I'm not impressed with the quality of the couplers that came with the set and I'm having a hard time finding the right part number for the existing couplers so I can cross reference them with other brands to,look at what replacements are available that fit the loco and rolling stock.
Also can the loco be fitted with a DCC decoder in the future as that is what I want my layout to run with? It's no big deal if it can't but I can't seem to find much info on this loco.