Fixer upper with a general contractor and permits in place?

Hi all, I have been flipping houses for several years but haven't seen this before and would appreciate your advice!

I have the opportunity to purchase a fixer upper that is half done. The current investor has a general contractor who has open permits for the entire project, so apparently I would take that over.  I would bring in some of my own subs. The numbers still make sense to complete it and sell it, but I am not familiar with the risks this might entail.  Any warnings? 

Thank you!

Patricia