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Thanks for cleaning that up, Dennis.  That is great advice.

I agree with others, and would disavow before it causes you issues.  That is the safest way to protect yourself.

I like your idea, and I think the fact that you are proactively looking at potential situations speaks volumes.  Having said that, my best advice would be the following:

1.  Make sure that you create unique content on your new site that does not overlap or duplicate anything on the current site.  The user experience should be entirely different between the two sites.

2.  Do not create links or banners all over the new site linking back to the other site.  Something thoughtful is fine, but tread lightly.  Powered by www.ClassicMuscle.com in the footer might be ok, but no guarantees.

If you create something of merit, there will be loads of value created in the lead gen department without relying on people clicking on links or ads.  The community will tell you what they want, and if you actively moderate it, I suspect you will find a lot of business.

There are so many factors that it is hard to say exactly.  It could be that it returns rather rapidly (days), or it could take weeks/months to come back, if not longer.  Have you seen your on-page score with MOZ for that keyword?  Have you made any recent changes that could be effecting the rank?  You may want to go back to a previous version of the page if you make dramatic changes.

I would remove them, to be safe.  Google sees them regardless of the "no-index", and I think that the cleaner you can get your data, the better off you will be in the long run.  While there may be no harm at this time, things always change.  I know one thing for sure, and that is that you don't want a duplicate content issue.