Hmmm. I'm sure the proper advice would be to dump them, but my freezer was inadvertantly switched off not too long ago and I had meat products in there that had started to defrost and whatever I couldn't get cooked up straight away went back into the freezer. I just checked it once it was defrosted before I cooked it, and made sure it was thoroughly cooked. It was all fine and had likely been out of the freezer longer than your cubes had.
Personally, if they were for myself (although not whilst pregnant
) and DH I'd put them back in, but as they are for your DS I'm not sure it's worth the risk tbh.
And, yes, your avatar is wonderful!