Supporters have concerns about your project too. Working through issues early on, save time later.
Not all your stakeholders are part of the same stakeholder arenas. There are different tables where decisions are made.
Never ever do a stakeholder analysis with your stakeholders present!
You need the right stakeholder overview to achieve support for your project. The Power-Interest matrix isn’t it.
There are always more stakeholders involved with your project. Some you already know, and others that define themselves. Don’t focus too much on the usual suspects.