Error when trying to edit Content Query Web Part in SharePoint 2013

SharePoint recurring events are tricky. This post is the single best resource for understanding the mess of recurring events

Understanding the SharePoint calendar and how to export it to iCal format

I don't think you're going to be able to do this in a CEWP but you can get the recurrences using something like

    SPList list = oSPWeb.GetList(listGuid);
    SPQuery query = new SPQuery();
    query.ExpandRecurrence = true;
    query.CalendarDate = new DateTime(2010, 6, 17);

    query.Query = "<Where><DateRangesOverlap><FieldRef Name=\"EventDate\" /><FieldRef Name=\"EndDate\" /><FieldRef Name=\"RecurrenceID\" /><Value Type=\"DateTime\"><Week /></Value></DateRangesOverlap></Where>";
    SPListItemCollection listItems = list.GetItems(query);
    foreach (SPListItem items in listItems)
    {
        // items["EventDate"].ToString()
    }

Then you will get recurring and non-recurring events that occur this week.

But beware that this is designed to be used by the calendar view so if you do, for example,

query.CalendarDate = new DateTime(2010, 6, 17);
query.Query = "<Where><DateRangesOverlap><FieldRef Name=\"EventDate\" /><FieldRef Name=\"EndDate\" /><FieldRef Name=\"RecurrenceID\" /><Value Type=\"DateTime\"><Month /></Value></DateRangesOverlap></Where>";

(Notice the Month setting) then you will get all events that should appear on this months calendar view - that is 31st May 2010 to 4th July 2010.

Having fought a bit with SharePoint on this, this is what I found:

There are two different ways the Snippets created by the Snippet Manager work. If they are put anywhere within the html code of your Masterpage or Page Layouts, they will have the exact same configurations as the ones you select on the Snippet Editor, and you won't be able to edit them afterwards.

However, if you put them inside a Webpart Container Snippet code, you will be able to edit the webparts when accessing the Edit Page feature on SharePoint. As you probably figured out, this only works on page layouts and not on masterpages.

I believe a way to have a dynamic footer, is to use a Content By Search Web part and point it to a specific List (Footer List) and on that list you can have a column with a Rich Text Editor type, and then you can create a specific Display Template that will render the list content as desired.

Hope it makes some sense.