Sorry for the delay. The past few weeks have been hectic with the move and all.
Yes you can use five gallon buckets to raise worms. The main issue will be the holes on the bottom. You can do this by drilling them at the bottom sides all around as well as the top sides. Space about 1" apart.
If you drill holes on the bottom and sit them on the floor, the holes will be useless.
Since five gallon buckets fit so tightly when one inserted to another I would not recommend allowing them to transfer from one bucket to another as you will cut off oxygen flow. African nightcrawlers are large enough to pull and sort to add to a fresh bucket. Allow the remaining cocoons and small worms to remain in the original bucket and bedding until large enough to move to another bucket if you desire.
If you have liquid coming from the bottom you will kill off these worms as you will definitely be to wet.
A second lid can be placed under the five gallon bucket to catch some castings that will be pushed through the bottom holes as the Africans work the bottom of the bucket.
On a side note since I use five gallon buckets to raise some of my worms since I screen them every two weeks for castings I found the best place based on pricing and opaqueness of the buckets is Lowes.