Be careful with the speed brake on the A320, pretty sure the 319/21 are different.
I saw this first hand with a new FO many years back, CONF2 and Full speed brake applied, then A/P disconnects and you are caught out.
Someone might be able to confirm, A319/A321 full speed brake applied with A/P is exactly that, full speed brake applied? In other words no nasty surprises if you disconnect like the A320?