Flan recipe calls for a blender; how can I make it in a mixer instead?
In this particular case, you'll be fine using a mixer instead of a blender. You are absolutely right about having the cream cheese at room temperature. Start your mixer at low speed and gradually increase to high. It might take a bit longer - other than that, just do what the recipe says.

Using a mixer instead of a blender would really only make a difference if you were expecting the blades to "cut" an ingredient, like making pesto from basil. Here, you are really only mixing, that's what mixers do best.