I would say no, crappy idea (so to speak). The more frequency overlap there is before you invert one, the more cancellation you'll get after inverting. So they might not fight with each other so much, but instead of two gloriously violent bull elephants going at it in the low frequencies, you've got too chihuahuas yipping at each other. I apologize for that ridiculous metaphor. But hell, what do I know, try it and see. Can't we all just get along?

It will only work if phase is constant. The best luck for getting a constant phase is to use samples carefully timed. Quite a bit of work really when a compressor will do the job much faster.

Good. I got the idea from the concept of phase inversion for finding an ideal spot for two mic recording. I thought it was a horrible idea LOL. Thought I'd give it a try anyhow.