Transplant pine seedlings

The previous owners of our house planted 5000 pine seedlings in the backyard. I noticed quite some are gone or didn't make it. They're all planted in a grid, so there will be clear gaps at some point.

At the back of my property I discovered lots pine seedlings growing randomly, many of them close together. They are 1 to 2 inches tall and look very healthy.

My idea is to transplant them to the spots where the planted seedlings didn’t make it and I’m wondering when I should do this. We can expect snow in a month, but not necessarily.

Should I transplant them right into their new spot or maybe into pots first?

If you're planning to plant them this year you want enough time before a solid freeze for the baby trees to establish their roots. I wouldn't transplant into pots, primarily because it's one more shock that they might not survive.

My own suggestion would be to wait until next spring if you can--many of them aren't going to survive the winter, and it's next to impossible to know which.

I'll probably give it a try this week and see how it goes. This summer I dug out 800 square foot of sod, to create a front yard with plants. Since I don't have enough plants, by far, I will put some baby trees in there.

I realize that might be a risk too, but I found so many seedlings that I can give it a try.

Added a picture of some of the seedlings that I discovered.