I'd suggest going all the way and lowering the oven temp by 25 degrees. A muffin is basically a quick bread baked in a smaller form. Which makes a quick bread basically a muffin baked in . . . I think you get my drift. Bake it lower, longer, and you'll be fine.

Yes. It would help to lengthen the cooking time by 5-10 minutes and lower the oven temperature by 10-15 degrees so you avoid, as la domestique says, overcooked outside and undercooked inside.Check for doneness after five extra minutes!

I would think so. You might have to cook them a bit longer. Keep an eye on the temperature to avoid over-cooked outside and undercooked inside.