I was working on a build with Ahsoka and Miranda, but I don't know if this is legal. If I take an action with Miranda (drop a mine) and I use Ahsoka's ability to spend a focus for another ship to take an action, and I use SLAM as Miranda's action can I take another action (drop a different mine) if I have advanced SLAM?

No, you cannot drop more than one equipped bomb upgrade per round and SLAM cannot be a free action

Got ya. I just looked up SLAM. Thanks