First time playing with snow, got some questions

This is Lily(white) and Bruno(gray). This year I decided to get them some snow to play with. They are indoor buns, so I filled up their secind littee box with snow. They (primarily Lily) enjoyed digging in the snow for snacks!! Tho, my bf got worried and we cut the session a little short, so my questions are:
– What is the longest they should be playing in the snow?
– How bad is it if they eat some snow while digging for the snacks?
– Anything else I should be avare of before we repeate it in the evening with a fresh batch of snow?

Thanks for the help in advance!