Good stuff and yes the .IFC file format works great in Revit MEP. If you need them to send something back for your own checks, the .IFC format as an import into Sketchup works great as well as the .dwg format. Check the “preserve drawing origin” checkbox in options when importing then check to see where their model lands. If it lands in the correct spot in relation to your model - awesome, if it lands offset from your model, this is where having 2D grids come in use - by moving their model with the grids as a group and lining them up with yours. You can check the level with a section in their drawings.
Check out this thread on BIM for a question I posted 5 years ago. If you scroll down AK_SAM, CAD110 and AndrewRubSketchup also provide some great insight on model coordination between Revit & Sketchup.
All the best!