At this late stage I don't think it would be such a bad thing for Katie to play qualiess as a warm up tournament. If she does make the main draw it will be too late for her to get in anywhere else and surely she could do with a few matches under her belt?
They can withdraw whenever they like. If what you're asking is when will players stop moving into the main draw that is when qualifying starts.
( Technically the withdrawal deadline is the same as the entry deadline.)
I think it is slightly different actually, though i stand to be corrected.
Once the Aussies have made the qualifying draw (probably sometime on Saturday or maybe Sunday Aussie time), if someone then withdraws from the main draw, they don't then bump someone up from the qualifying draw (ie the qualifying number one seed), but instead allocate the extra place to a lucky loser. That means Katie is very dependent on someone withdrawing from the main draw in the next few hours, if she is to get a slot in the main draw.
Much debated on here I know, but I don't subscribe to the view that she is better to come through qualifying. I would far rather someone withdraws in the next few hours and Katie to then have a week's rest.
No info anywhere on when the Aussie Open Qualifying Draw will take place. I am guessing that the lack of publicity regarding this means it will just happen and then be posted on their official website afterwards.
Any info on when it will take place will be much appreciated, but I did quite a long internet search and found no useful info. It does appear that qualifying is scheduled from Monday to Thursday. so perhaps it will be a draw on Sunday and not Saturday, though part of me thinks that whoever is playing on Monday will need a reasonable notice of the draw and start times, so perhaps a Saturday draw is more likely. Katie B will be so unlucky if she misses the main draw by one place.