In order to modify the selected colors of the series you would need to use you own SelectionPallete, similar to what you are using in Pallete property.
chart.SelectionPalette = CustomPalettes.CustomSelectionDark;
Currently, Axes titles are not supported, so you might want to use labels and position them beside the chart. I have logged this as a feature request in our feedback portal where you can track its progress - https://feedback.telerik.com/Project/168/Feedback/Details/239493-chart-add-support-for-axis-title
I have also updated your telerik points.
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