revan - The little bluey does look pretty normal for a baby. The larger bluey seems, by the pics to be more than 6 months old and as "SuburbanMe" suggested earlier there could be a problem in having them in the same enclosure at this point in time due to domination issues.
If possible, perhaps putting the little one in another enclosure on its own might help. or you could divide the enclosure to separate them.
I think the change of environment has been very stressful for the little fella and a lack of hiding places might be making him feel very vulverable and exposed.
Also, when feeding move away or hide. Sometimes they won't eat if you're there.
I know its not a substrate thread but I don't think the eucy mulch is a good idea although it looks good. Imagine for a moment if either of the blueys accidentally ingested the mulch, could cause medical issues.
Keep presenting the food and hopefully he'll settle down soon.
Good luck. I now its a very stressful time for you.