Is it permissible in Islamic law to work on a telecommunications engineering project to develop data transfer between mobile devices, which includes both theoretical and practical components? And is Istikhara (guidance prayer) useful if one is hesitant about it?

Electronic service is a noble service if utilized in a beneficial and proper manner. The default ruling for it is permissibility, and there appears to be nothing to prevent it. One must avoid religiously prohibited elements in the theoretical aspect, and Istikhara (prayer for guidance) is beneficial as long as the matter remains within the realm of the permissible.