Not popping through soil yet

Some just need more time. Other common issues are planting too deep or packing the top soil too much. Last possibility is the soil was too wet and they suffocated. Plain old genetics is also possible but unlikely. You as the grower should know where you went wrong based off of this info. Good luck my friend!

Hard to say, week seeds, too much water, too cold, too dry. To reach 100% success rate several things can be done: using a heat mat, humidity dome, soaking the seeds in water before sowing them, using the paper towel method.