Office 365 SharePoint team or project site, Planner, Yammer and Groups integration

We're showcasing Office 365 functionality but there are a lot of relevant questions coming from our customers. One which I would like to get a better understanding of is the following: 

If you have a project that you're going to run with one or more suppliers, ultimately collaboration is key and for this we would want to have a dedicated SharePoint site (team or project) for file storage and other content, Yammer for communication and Planner to manage the project. As I understand it now, Planner integrates with Groups so we're fine there. But I don't see Yammer integration with SharePoint and Planner? Planner does allow posts, but I have no idea where that ends up? I assume it's in the Group that shows up in your Outlook client? 

The SharePoint Project site template leaves you with a Newsfeed which I'd prefer to come from Yammer and a simple SharePoint list making up your Tasks list which I'd prefer to come from Planner. 

So a SharePoint Project site seems outdated. 

All of this seems awefully counter-intuitive. 

I've checked the SharePoint web parts and there's nothing related to Yammer, Groups, Planner or anything of that sort. Seems a pity that you can't use a SharePoint site as the foundation for a project with the relevant web parts to aggregate communication and tasks using web parts. It's not ideal to be jumping around between Outlook, SharePoint, Groups, Planner... the list goes on. 

Have any of you streamlined this kind of configuration where you get a more seemless end result?