orange A319/320 ops:
Yellow HYD pump ON before Eng 1 start,
Eng 1 start.
After start 'scan' (setting flaps/trim APU Bleed OFF), but no after start checklist yet;
clear groundcrew, call for taxi.
When time to start Eng 2:
PNF actions all items from QRH 1-eng departure checklist
Yello HYD pump OFF,
APU Bleed ON,
Start Eng 2.
When start sequence finished, start timer (2min required before takeoff power)
APU bleed OFF,
APU OFF,
After start checklist.
Normal procedures follow from there (flying control check, takeoff briefing review, takeoff checklist etc.)
The rest of the pre-takeoff procedures usually take less than the 2 minute waiting period required between eng 2 start and takeoff.
To answer your specific questions:
- YES
- APU Bleed. You must be stopped to use crossbleed.
- during taxi
- PNF starts Eng 2 using the specific checklist. PNF can be CM1 or CM2 as we can taxy from either seat on the A320.
HTH
GL