As long as the cells can not develop into an embryo, there should not be a moral difficulty. They may be able to develop into differentiated tissue in the right environment with the right signals, but still be unable to direct their own developmental path that would make them a complete organism - a human bein.
Essentially correct. Embryonic stem cells are pluripotent—can generate the cascade of tissues which build a human body’s psrts. What would be ethically wrong would to back the skin cell up to the totipotent stem cell stage and I don’t read that such is their goal since totipotent stem cells when tried for treating diseases have egnerate teratomas and in some cases killed the patient being treated. ... But given the number of dead soul progressives in stem cell science, I will guarantee some little demigod will try it in order to see if he/she can grow an entire embryonic being.