Sequencer questions

I’m going to make a video in the Sequencer. So my questions are:

  1. How to make a character fire their gun in the Sequencer? Is this done by pressing a key (the letter W on the keyboard)?

  2. Can I have four characters fire their guns at the same time?

  3. I will be using animation packs. I will need to make Blendspaces for these animations for the Sequencer, correct?