Acid
The wording for acid is a bit confusing, if i used it 3 turns in a row, would it put 2 acid counters on, then 3, then 4 making 9 in total, increasing my rank by the same amount?
The people who are being quickened should post their second actions.
Also reducing the roll using fortune can't activate Complete Misfire, i think.
To your question regarding Acid, yes. Think of 'Acid' as the weapon Arsenic.
(damage over time)
First use = 4 direct damage, 1 damage over time tick (1 damage total)
Second use = 4 direct damage, 2 damage over time tick (3 damage total)
Third use = 4 direct damage, 3 damage over time tick (6 damage total)
Fourth use = 4 direct damage, 4 damage over time tick (10 damage total)
Your other questions however; Quicken affects the -next- round's actions, and Fortune can trigger complete misfire in the opposite direction, as dice rolls can 'wrap around'.