Hi Andy,
Welcome to the forum,
I am having a little trouble reading your romanization as I haven't learned to read it.
I am guessing you mean 어때요? and 은 는요? and 을까요 를까요?
They are different, however I could see some situations where they could be used in similar situations.
The first situation Mcdonalds 어때요? Is like how about Mcdonalds?
The second Mcdonalds 는요? Is like directing the conversation towards Mcdonalds. Maybe you were thinking of going to KFC, but you suggest Mcdonalds instead. So it could be translated as how about mcdonalds as well, depending on the context...
The last 을까요 를까요 is a bit strange because I think you need a verb, for example - Mcdonalds 같이 먹을까요? How about eating mcdonalds together?
While all these sentences can be translated similarly, I think there is a great deal of difference in nuance.
Hope that helps, Julia, manyakumi and Trutherous are some users who are a lot more knowledgeable than me, so hopefully they post and clarify more.