Hi, welcome to HBT and the homebrewing! I moved this to the Beginners forum, where more folks might see it. Using food grade pickle buckets would be just fine. You want to be careful with plastic, generally, to avoid scratches in the surface. Its hard to clean inside the scratches and the wild yeast and bacteria can grow in those scratches. So, don't use scrubbies or anything that could scratch the surface when you clean it the buckets. If you use soap, rinse the bucket very well - soap is bad for beer.