We need an expressive headline, like "thank you for a wonderful year" — which typeface do we use?

Museo Sans: for a large headline, bold 700 at a bigger size, or, as an exception, light 300 at 40px and above.

Size and weight give a headline its presence without a second typeface, and a second typeface makes the material look like something other than Aleris. Black 900 is almost never used, so try 700 at a larger size first.