I can not say about the members of the development team. But I doubt that there is someone from the official Stellar team. I think that just guys made their fork based on Stellar.
There is in this STELLAR LIGHTNING project whether representatives of the official development team of Stellar are not really important. There are enough talented programmers in the world. I understand that the Stellar code is taken as the basis of the project and then the coin will go its own way.