i am new to all of this, can buttercream be frozen and if so how long for

yes, but unsure of time!

When properly prepared for freezing it can be kept for at least a year - depending on the recipe used.
If it's a 'straight up American b'cream' it's best kept in a glass jar in the fzr. I have used plastic containers but then your time is shortened - say about 6 months.
Depending on how much icing there is, I use the smallest container I can find - buy them at the $ store - get like 4 for a $, putting each color in separate container. Baby food jars are also great for this