renovatibg a landmark brownstone in Bed Stuy?

I’m purchasing a 3 family bownstone on a landmark block on halsey street in Bedford stuyvesant.  I will need to do some kitchen & bathroom renovation work on all floors including finishing the basement and completing an existing extension at the back.  I will also need to bring the house up to code.  I believe I may need an Engineer or an Architect, but am unsure of everything. I’m working on a low renovation loan budget.  Any advice will help. Thanks.