Adorable photos, makes me think of Pichu, he recently passed away
I still have two robo girls though...Bah was about to post about the yellow nesting, but saw you PS remark, well for anyone who reads this in the future and doesnt know...
Hazardous nesting material! That woolly fibrous stuff is notorious for causing injuries to hamster, either through ingestion or because it tangles around a limb.
Soft paper bedding is best. Try taking un-dyed and unscented toilet paper or paper towel and tearing it into strips for your hamster. Thats what I use and it works great.