TundraSnow Kids Boot (Toddler/Little Kid)

My 2yr old son wears a 6.5 in shoes. He has very wide feet especially down by his little toes. Any one know how wide they are?

My 2 year old daughter wears a size 7.5. but can fit into a 7. do these run on the bigger side or smaller? wondering if i should size up?

Are they slippery when walking on the ice?

Are they pretty heavy?