- passive aggressive: This is a personal judgment. He was passive aggressive in what way? - excluded you from the team: How was he excluded? Was he not invited to events? Or did he not get good projects? If you are a temp with potential performance problems, it's normal that you don't get the cool projects. - code was awful: Again, is this a sentiment shared by other members of the team or is it just one junior engineer being super opinionated about something - long term maintainability: I don't think he was there for long - missing roadmap because poor design decisions: Again a junior opinion, running projects are complex with many different variables, you fail meeting deadlines for various reasons, there's never a single reason, and that reason is never "we had a bad piece of code written by one guy". I don't think OP has the historical context of that led to the that code.
When I hear all this feedback coming from a temp, all I hear is they weren't a team player, they don't know how to be diplomatic and most of the things they are saying are coming out of frustration and have no substance and is not actionable.