How far ahead can I make a doll cake?? I will be covering it with mmf, still not sure on the fillings though. If I make it Monday or Tuesday, will it last until Sunday?

it should, the fondant usually seal in the freshness, keep it in the fridge if you can, that will help.

I think Monday or Tuesday is a bit early for a Sunday cake..I think starting maybe Thursday or friday may be better.

If you make the entire cake then freeze, it will be fine. I do it all the time. Are you talking about a barbie doll cake? I made one for my daughter and froze it for a month, as I was going on holidays. Tasted fresh- no one would have known.

My rule of thumb is no earlier than 2 days before the event unless I am freezing the cake.