moonflower seeds

[Paperwhite newbie]

Slowly but surely getting rid of some of the extra moonflower vine seedlings, gave a pot with 2 in it to the neighbor across the street, going to give a friend up the street 2 pots I think. The datura seedlings are doing very good and I can see the true leaves starting to grow in the middle of the seed leaves. So lets hope that transplanting them when they are this young does not kill them, I dumped all the potting soil they were in on newspaper, and gently separated them. Then went out back and got more potting soil and put them in their separate pots, hopefully they will survive, I did not break or tear any of the roots and I handled them VERY gently. Still have 8 left, thankfully I think all of them have sprouted, I did not see any left in the soil. By the way, how long can you keep potting soil and it still be good? I have had this soil since last summer. One other question, how close to the leaves is the soil supposed to be?