I would say they are too wet .
The yellow one looks like dampening off .
Too much water and the soil did not agree with the tobacco .
I would say when you pulled the plants up and transplanted the roots on the sick ones was tinny and possibly brown . Thye may have only been laying at the top of the soil .
http://tobaccoboard.intnet.mu/prod04.htm#Damping
http://www.ces.ncsu.edu/depts/pp/notes/Tobacco/tdin007/tb07.html
The yellow one looks like dampening off .
Too much water and the soil did not agree with the tobacco .
I would say when you pulled the plants up and transplanted the roots on the sick ones was tinny and possibly brown . Thye may have only been laying at the top of the soil .
http://tobaccoboard.intnet.mu/prod04.htm#Damping
http://www.ces.ncsu.edu/depts/pp/notes/Tobacco/tdin007/tb07.html