You do know you can use open source code, if you read the licensing agreement and give credit where credit is due. Hence why it is open source, for people to use and build upon. You also make reference to a team, if someone on your team is lawyer and didn't point that out then he should fired LOL Also did you know mysql is open source you better not use it. LMAO Thank you for the laughs, with your commercial fail project LMAO
Unfortunately it's not as simple as you put it. You are mistaken. While there are numerous open-source licenses, they are typically restrictive in how you can "freely" use them. Most of them, including GPL, would require you to release your derivative work that's based on the open-source code or at least make it available upon request. Others may have different sets of restrictions. There are of course situations where it "can" be used, but that's not the norm as you are suggestion.
My team does not have a lawyer, as I do not represent a company, but I'm well-vested in the software industry to know what to avoid.
You are also confused about "using" open-source software like MySQL and "incorporating" the open-source code into your own. They are distinctly different.
Also, whether the project fails or succeeds, should have no effect on the developers as this is strictly contract work for deliverable that is NOT based on profits.