Recently Harvested Douglas Firs! What next?

[LMZ]

Hi everyone, I recently harvested 6 Douglas Firs from Oregon and brought them back to Kentucky (6b) as a carry-on. I potted them 2 weeks ago and they seem to be doing alright and getting used to their new home. I currently have them (pictured below) in pots filled with potting soil sitting on a table in my backyard. On a clear day they receive 6-7 hours of direct sunlight. The occasional summer thunderstorm has been their water source for the past two weeks. Now that I think they're going to survive, I'd like to ask for styling techniques and the process of bonsai-ing a Douglas Fir. My ultimate goal (if all six survive) would be a Douglas Fir forest composed of all formal upright but differentiating trees.

I've included pictures of all 6 trees. I believe there are 3 "old" trees and 3 "young" trees. Maybe some are 6ish months and the others are 18? Please correct me if you have more experience with Douglas Fir ages. Any styling techniques and tips would be greatly appreciated! Thanks!
(If you would like to refer to a specific tree, I've number the pictures)

TREE 1:



TREE 2:

TREE 3:



TREE 4:


TREE 5:

TREE 6: