I'm no pro but here is what I used, I started these in happy frog soil. Then moved to roots organics 707 soil. They were kinda slow at first, the worst thing I did was transplant these several times. Which is sounds like you are ahead of at the moment. It stunted the diesel and that thing hasn't grown an inch in 1 month. Also don't be too quick to give bloom nutrients, wait. You will have preflowers in a little while and the tendency is to jump right in and help them bud, but just wait. That is just about the time they really start to put on some serious growth.
If you have some that have the seed casing still on them you can carefully remove the seed casing and allow them to grow. I've had to do that before and it's fine. Just give them some time and I bet they will take off. I water the seedlings very lightly and almost daily, it was just enough to get them a drink but would dry up by the next day. They were not sitting in mud though.
Welcome to AFN and keep us updated on your grow and don't be afraid to ask questions. Lots of really great people on here that are more than happy to share help. Not just out to be the king and keep secrets to themselves.
One day you'll be sharing experiences as well!!