TheSword
Legend
If a person spits in another persons face, is that an attack? If a person pushes a lever on a scorpion that causes a bolt to fly down a corridor impaling someone out of an onrushing mob, is that an attack? Is pushing a Boulder off a city wall onto someone an attack?You're free to rule as you wish in your game, of course, but the fact that the Help action to grant advantage in combat is specifically not an attack has been a long settled issue, rules-wise. Basically, you're saying that the word "attack" in the Invisibility description isn't the game mechanic term, it's a broader natural language usage indicating any action that might hinder or inconvenience the target.
I personally don't agree, and if my DM ruled that way, I would be disappointed and ask for the opportunity to rechoose my Pact. The invisible familiar granting advantage is the primary mechanical benefit of Pact of the Chain.
I would happily rule that all of these are attacks in the broader sense, and yes would break invisibility even though I don’t believe they would need an attack action.
Invisibility has to view attack in the broader sense otherwise it is too easy for players to gimp.
If you want to use your familiar this way, hope for a generous DM.