Thanks for contacting us regarding your question.  If your original trunk did not survive, and what you are growing are seedlings, then cultivars do not usually produce seedlings that are exact to them.  They typically are the original redbud.  Are the younger shoots from the original root base? 

Here is some additional information regarding this cultivar:
It does not transplant well, and should be planted when young and left undisturbed.  typically a carnival of color in early summer as new leaves emerge, ‘Carolina Sweetheart’™ redbud starts out with pink flowers in early spring. Then the new leaves emerge purple, but over time, they gain various shades of white, green, and hot pink. Eventually, the leaves turn green in the summer. 
Additional information can be found about this cultivar at: https://plants.ces.ncsu.edu/plants/cercis-canadensis-nccc1/