Is there anything that can spur individual bone growth to mitigate brachydactyly type e?

Yes. The best resource for such a question would be a hand surgeon. I have seen case reports of treatments with various measures, from surgical implants to types of traction; it was the traction that caused actual bone growth. In general, though, it is my understanding that in most cases treatment is not necessary.
Maybe. I habr reaf about using min ilizarov devices to lengthem these bones slowlyvery sphisticated care child closest pediatric hospital tjry may have apediatric jand surgeon fixing lbster claws and otg moresevere deformity.