Not sure I fully follow your issues here--??
However, have you looked into IFC format? There are a lot of posts and information on the web regarding Revit and IFC file compatability.
The truth is, there is zero chance that you will take a Archicad model and bring it into Revit and have a 100% fully functional Revit model--
there is no "magic conversion" application or plug-in that I am aware of.
The 2 platforms are similar, but yet very different and were never designed to be bi-laterally compatible.
Same thing with bringing in models from Sketchup, 3dsMax, Microstation, FormZ, AutoCad 3D, etc.
BIM is a very ambiguous term. The different flagship BIM programs all have merit, but were created by different companies, with different customer-bases,
and are competitors in the AEC market. IFC is a great idea--and perhaps someday there will be an "open-source" BIM format--but we are no where near being there yet. So--to avoid frustration, learn what the possible options are, and do your best to accept the current limitations and then decide on a SINGLE BIM platform and roll it out--from the top down.
Take a look here, if you have not already:
http://www.graphisoft.com/downloads/interoperability.html
Cliff B. Collins
Registered Architect The Lamar Johnson Collaborative Architects-St. Louis, MO