Source code sent to pool owners 1-2 hours before the launch. Pools may works earlier than launch time if pool owners work fast enough.
Dont worry about instant mine. From block 1 to 180 only have 1 coin, mining all 180 blocks take about 3 hours. So fair enough.
3 hours ?? too damn long, dev
Dont worry, low-dif-block can be found very fast, so it may just need 2 hours or less. People have time to jump in with no missing coins.