Too cold to plant seedlings?

September, I ordered some treelets (chestnut oak, redbud, sassafras) from Tennessee Wholesale Nursery, they finally arrived *today*.   Still in its box on my porch.

Tonight's low:  27F.  Low tomorrow night, 20F.  Then a week of above freezing lows follows.

I think I have three options:

1.  Plant them immediately.  (Buuuut, the roots and surrounding water will freeze, especially tomorrow night.)
2.  Keep the treelets in the box til Thursday afternoon, after the freeze.
3.  Keep the box in the basement (68F) til Thursday.

Any option better than the others?    Or is the answer simply:

'Any of the three options will be fine, the seedlings will wake up come Spring, just don't pour Roundup or something on them.'

i would plant asap. in your area the ground doesn’t freeze deep when it does. one night at 20 won’t freeze inches deep. i highly doubt their roots will freeze, and they’ll be happier in the ground.

I planted.  Watered, added a bit of mulch at the top.  We'll see come Spring if it was successful, I'll update if I remember (which is not a given any more!)