Implementing a few special attacks for a boss

I'm trying to make a short game where you fight a boss in a sort of 3D bullet hell form, and I'm trying to figure out how to implement some of the attacks I had in mind. He can currently shoot pellets at the player, but I want him to be able to do a few more things.

1. A sort of "pillar of fire" attack, where circles appear in random parts of the arena in quick succession and then launch a pillar of flames after a few seconds to give the player a warning to move.

2. A moving laser trap, where lasers spawn in patterns and sweep across the room with a gap for the player.

3. Similar to the laser traps, but vertically, so a group of lasers that randomly move throughout the room. I think I can do this with the same technique that I use to make the boss randomly move throughout its area, but I'm not sure.

I know this is a bit of a big request, but if I could get some suggestions it would be a big help because I don't really know where to start here.