She certainly does not look grulla to me. All the hairs on a grulla should be that mousey gray color. They should not appear roany with different colored hairs.
She looks more like a roan. But I don't know the genetics of it. I think roans are like grays in that one parent has to be roan. So I doubt she is a roan either.
Based on her parents I would say brown. But she really doesn't look brown either.
All I can say for sure is that she is beautiful and TALL.
PS. How tall is she?