Both of the trees are very brittle and dry. They are both either pices mariana or one of them may be a pinus aristata. I started growing them in the summer and they were fine but when winter came along they started to look like this. I water them when the soil starts to look dry. Also I keep them in my window seal at all times (there’s a radiator right below) I got them from a kit off of amazon also.
Regardless of what species of pine they may be, they would be far better off outside in than indoors.As long as they experience deepening overnight cold, as is characteristic of normal fall weather, they will be able to tolerate freezing temperatures. Alpine species, such as p. aristata can tolerate cold approaching 40 degrees below zero.
The primary problem with being indoors is that light levels are too low to sustain the plant. Bright light indoors is about the same luminance as deep shade outdoors. Pines do best in full sun.
To the point of your seedlings, they are dead. After you have killed enough of them you will come to recognize the off color (sort of grey-ish) green that is the first indicator of serious trouble. Death occurs as long as months before needles turn brown.
When you try again, time it so that the seeds sprout in spring and leave them outside. Your results will be more enjoyable that way. Smaller pots, say 2 to maybe 4 inches across, will be better until they are at least 2 years old.