Think of it as a creative co-op mission. Start by understanding their perspective—what problem are they trying to solve? Compare their suggestions to your goals, finding overlaps where possible. Propose small prototypes to test their ideas without overhauling the vision. Collaboration thrives when ideas feel heard but the game stays on course.

From my experience, if somebody volonteers an idea for a project in which they have little to no stakes, it's not their idea. In this case though, it is a good thing. That means whatever they are suggesting has already been made elsewhere in a different game or context and that means you can easily review why it worked (or didn't) then and why it's not already in your game design and if it would actually work (or not) if included. Always keep in mind the game you want to create, stay original, but don't forget you can learn from the mistakes (and sometimes the successes) of others, especially when some want you to blindly repeat them.

I do like constructive feedback or suggestions on my projects. It is always good to see problems or changes from someone else's perspective. Even if their vision doesn't fully align with yours, don't throw away potential suggestions. You can always take parts of their suggestions and modify them to fit your current project. If they make suggestions, it means something doesn't work well or seem right to them so it may be worth taking a second look.

Treat everything in a case-by-case basis. Group similar feedback on larger points (e.g: "Mechanic x", "core loop", "retention") and then take each of them individually and see how they align with your core loop and vision, if there are concepts or ideas that would work. Take those and analyse and refine them to fit your project.. If some is wildly against the vision, understand the reasoning behind suggesting it- why would an end user think this a desirable change, would be interesting to try and do a quick prototype and see how it interacts with the rest of moving gears? Ultimately, it's all about taking what will work with your vision and ignoring what won't. But that doesn't mean you can't use feedback to question such vision.

Integrating teams, make everyone feel valued... is it some non profit shelter house for broken people or a team of people who want to make a game? Align everything with core concept. But still be open to new ideas. They almost never work out of the box, bit it's also very rare if you can't extract some good idea from any feedback. Focus on product, not on devs. If you need to baby sit them you will fail because you have picked the wrong team.