Couple wants a three tier...12, 9, and 6 and they want Red Velvet on bottom and also on top and I thought I would do a white cake with raspberry type filling in middle.

Should I have the same icing on all three layers? They said something about a cream cheese frosting for the red velvet but I didn't know how that would work with the middle layer. I am also worried about how a cream cheese frosting would hold up for an outside summer wedding.

Any help would be greatly apprecaited.

Cream cheese icing is delicious but it's not heat tolerant and it's kind of a pain to decorate with.

If you do use it I would do it on all the tiers so the look is consistent, and advise the couple that the cake shouldn't be left out in the heat for any length of time.

Would a buttercream be better on on layers?

You could do the cream cheese icing as a filling only and use BC on the outside. But I would still advise them not to leave it out in the heat.