Can answer a couple of your questions:
Yes - QFCollege online is available for ground staff. Some really good courses available and you get a certificate for most of them.
The benefit of being ground staff before flying is that you will have chance to work alongside crew and get a better feel of the day to day job. You would also get staff travel benefits after 6 months.
The other thing is that you would gain a bit of seniority. However its unlikely you would get enough to affect your trip bidding because ground staff don't 'bring over' their whole seniority.
There are around 700 long haul crew on the list to come to short haul and about 150 on the list to go to long haul. I wouldn't say short halu is the way to go necessarily because our flying is under threat from the proposed 'budget airline'.
The main reason long haul crew want to come over to short haul is lifestyle. Basically short haul crew are home more often than long haul crew and there are a lot of LH crew who started flying when they were younger and now they have families etc. they would rather be home than away for 12 days at at time.
LH pays more though so it all depends on what you want.