I think you are asking the wrong question, at best you are asking it way too early. You should be 100% focused on recruiting members for your team, not buying

I think you are asking the wrong question, at best you are asking it way too early. You should be 100% focused on recruiting members for your team, not buying fancy tools for the non-existant team. But to the question at hand. It is pretty hard to tell you what software you will need without knowing anything about the existing software or the type of software you are tasked to build. Personally, I would let the new team members you hire pick their own hardware (within a realistic range).