Micro four thirds - does the crop factor apply to MFT lenses as well?

...yes, they are Equivalent, regardless of the electronics, where "Equivalent" is defined as:

http://www.josephjamesphotography.com/equivalence/#equivalence

Equivalent photos are photos of a given scene that share the following five parameters:

• Perspective
• Framing
• DOF
• Shutter Speed
• Display Dimensions

Now, when it comes to noise, yes, there will differences, but who would say, for example, that f/2.8, 1/100, ISO 200 on an EM5 is not equivalent to the same settings on a GX1?