I have figured out how to add tabs to my custom section template using a umb-tabs directive and a tabs object in my model... with a properties array:

 return [
                    {
                        active: true,
                        alias: "Feature Detail",
                        label: "Details",
                        id: 1,
                        properties: [
                            {
                                //id: 1,
                                alias: "title",
                                label: "Title",
                                description: "Short title/name to describe the ad/campaign.",
                                editor: null,
                                hideLabel: false,
                                validation: { mandatory: true },
                                value: model.title.value,
                                view: "textbox"
                            }, // title,

....

But can I add a tab via my own directive? as well as the tabs array?

something like:

 return [
                    {
                        active: true,
                        alias: "Tab1",
                        label: "Tab 1",
                        id: 1,
                        properties: [
                            {
                                //id: 1,
                                alias: "title",
                                label: "Title",
                                description: "Short title/name to describe the ad/campaign.",
                                editor: null,
                                hideLabel: false,
                                validation: { mandatory: true },
                                value: model.title.value,
                                view: "textbox"
                            }, // title,
                     ]},
               {
 active: true,
                            alias: "Tab2FromTemplate",
                            label: "Tab From Template",
                            id: 2,
                            template: "/path/to/view/file/or/template",
                            data: _myDataToPassToDirective
}]

EDIT: I figured out that in my view where I added the directive, I wasn't passing in "node", my call to the directive looks like this:

<umb-content-node-info ng-if="tab.view == '_umbInfoTab' && node.id" node="node"></umb-content-node-info>

In my controller I define "node" on the scope:

 $scope.node = {
            id: null,
            owner: owner,
            allowedTemplates: [],
            documentType: { id: null },
            template: null, // templateAlias
            releaseDate: serverTime, //
            createDate: null,
            removeDate: null,
            published: true,
            urls: [],
            createDateFormatted:'LLL', // dateHelper.getLocalDate($scope.node.createDate, obj.currentUser.locale, 'LLL'),
            releaseDateYear: null, // $scope.node.releaseDate ? ucfirst(dateHelper.getLocalDate($scope.node.releaseDate, obj.currentUser.locale, 'YYYY')) : null,
            releaseDateMonth: null, // $scope.node.releaseDate ? ucfirst(dateHelper.getLocalDate($scope.node.releaseDate, obj.currentUser.locale, 'MMMM')) : null,
            releaseDateDayNumber: null, //$scope.node.releaseDate ? ucfirst(dateHelper.getLocalDate($scope.node.releaseDate, obj.currentUser.locale, 'DD')) : null,
            releaseDateDay: null, // $scope.node.releaseDate ? ucfirst(dateHelper.getLocalDate($scope.node.releaseDate, obj.currentUser.locale, 'dddd')) : null,
            releaseDateTime: null, // $scope.node.releaseDate ? ucfirst(dateHelper.getLocalDate($scope.node.releaseDate, obj.currentUser.locale, 'HH:mm')) : null,
            removeDateYear: null, // $scope.node.removeDate ? ucfirst(dateHelper.getLocalDate($scope.node.removeDate, obj.currentUser.locale, 'YYYY')) : null,
            removeDateMonth: null, // $scope.node.removeDate ? ucfirst(dateHelper.getLocalDate($scope.node.removeDate, obj.currentUser.locale, 'MMMM')) : null,
            removeDateDayNumber: null, // $scope.node.removeDate ? ucfirst(dateHelper.getLocalDate($scope.node.removeDate, obj.currentUser.locale, 'DD')) : null,
            removeDateDay: null, // $scope.node.removeDate ? ucfirst(dateHelper.getLocalDate($scope.node.removeDate, obj.currentUser.locale, 'dddd')) : null,
            removeDateTime: null, // $scope.node.removeDate ? ucfirst(dateHelper.getLocalDate($scope.node.removeDate, obj.currentUser.locale, 'HH:mm')) : null,
        };