Virtual Microphone using Mic Impulse Response
Will this work? Well, it will do something, but it will not magically make one microphone sound like another. A microphone is much more than a signal receiver with an impulse response. The character of a microphone is determined by its directional characteristic and how it couples to diffuse and direct field components, the kind of coupling to the pressure field, the nonlinearity of the membrane and integrated preamplifier, the noise of the membrane and the electronic components. 

You will only be able to capture a small part of all that with an impulse response, and very likely exactly not the part of a microphone that is responsible for the praise of its sound.

But even if you ignore all that, you're still left with the problem of deconvolution that is not trivial, especially in the presence of noise of a potentially unknown character. Your spectral division approach is rather naive and will work to a certain degree. If you want to get good results, you will have to take a harder route and you will probably not even in that aspect get what you imagine. Also, you will always have to start with a very good microphone. A bad microphone does not allow for such a simple improvement usually.

In short, even if I sound overly pessimistic: No, this will not work how you probably expect it to. If you want to do this to start a research project then you're good. But it's not going to be a plug and play product for microphone aficionados.