I don't think you're giving enough neccessary information here. Is his role just chunk out the code, help with backlog and fix some bugs? Or he's going to be re

I don't think you're giving enough neccessary information here. Is his role just chunk out the code, help with backlog and fix some bugs? Or he's going to be responsible for making strategic tech decisions and then communicating with entire future tech team about them? Obviously the latter is a much worse fit for a part-time, low-commitment employee. What about these features he'll have to compete - are they well-defined? Has he done similar things dozens of times before, or will he have to research it as he goes together with everybody else?