Snow After Repotting

My maples and larches have started to break their buds. As per bonsai literature, when this happens we repot the trees. However, Victoria's weather is so mild that the buds break before winter actually ends. Hence the "I've already repotted some things, yet it is time for the last sub-zero cold snap."
It is all about aftercare.
I bring my plants right up against the house, where the radiant temperatures of the house will keep the repotted plant a few degrees warmer then outside is in general. Others put their repotted plants in an unheated garage or shed. Still others have a greenhouse to leave the plants in. One could put their trees into a deep pit, where the ground will insulate them.
The only other solution is to wait until after the early March Victoria cold snap. Most of us know it is coming. And the trees whose buds have broken aren't going to be growing very fast when the temperatures are so low. So if the tree doesn't bud out too early, it is ok to wait.

Maple Seedlings!

I usually pick up a handfull of seeds from a japanese maple I know that seeds regularly in fall, and I throw them into a 'soiled' flat to come up in springtime.
I happened to find that many seedlings come up under the tree the next spring. I collected many of these in a ziplock bag, with a wet paper towel in it, and transported these new trees home.
Well, it is ziplock bag time for the next month! I saw the first crop of seedlings break their shell on Feb 25.
I will wait another week for my first harvest.
1) I had better have time to pot them up fast!
2) I have to have soil too - something I am low on right now.
3) if I wait to long, the seedlings will lose growing time this year.
Let me elaborate on point 3. Seedlings (in general) grow only from the energy they have stored within them. They do not need any nutrients or anything from the environment. After the first quick burst the plants begin to utilize their environment to generate more energy and structures. If the seedling is disturbed during the first flush of growth, it will quickly recover and re-establish itself.
So damaging the maple seedlings roots by pulling it out of the ground, and then storing the plant in a plastic bag with 200 of its brethren for a couple hours while I finish my errands; won't harm the seedlings a bit - if I do it to the seedlings first couple of weeks of their life.