Its strongly recommended to agree and share a common grid file early before each consultant charges on with their own models. Trying to reposition multiple models, each with their own origin once you are down the documentation path can be painful.
I have not quite figured out all the details yet, but when exporting from ArchiCAD to IFC the AC Project North is stored in the IFC file. When you view this file in Solibri it will look as it does in ArchiCAD (Project North has no effect), however it appears that when Revit imports the IFC file it reads that Project North setting and rotates the model accordingly to match the Revit True North. That's what is causing your model to be rotated out of position in the Revit file. There is also funny business between the AC Project Origin and Revits origin, the latter is not fixed but can be repositioned to 'real world coordinates' without actually affecting the model location. You basically pick a point and say this is X,Y map grid whereas in ArchiCAD you physically need to move the model relative to the fixed origin.
Given that you are now both using (independently) established locations for your models I think the easiest thing will be for the Structural engineer to reposition your model each time they import into Revit. As long as your IFC file contains the Grid its very quick to reposition a linked file in Revit - only takes a couple of clicks. If you get into the game of actually trying to move one of your models so that the exports align expect to waste a lot of time in trial and error.
Now on to levels ... you are both using exactly the same stories/levels aren't you?
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5