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Well, here are some more possible issues....

1. Are you sure the redirect to the English page is a 302 and not a 301? As Dr Peter suggested - check the headers.

2. Google has said that in cases where it believes the 302 is a mistake it will treat the 302 as a 301....if this is the case, there's really nothing you can do, besides getting rid of the 302 and using a meta refresh instead.  The meta refresh is commonly used in situations like yours, and while not a perfect solution, it would seem to be better than using a 302, which is typically not a good solution at all anymore.  I'd bet this is your issue.

Tim the keyword tool, while helpful, doesn't give you every metric that makes or breaks SERP performance.  One BIG metric it doesn't give you is the number of links with anchor text for your keyword.  It may be that stainedconcrete.org has a considerable number of incoming links with the anchor text "Stained Concrete Flooring."

Also, the site may have other trust factors that rate high with Google that don't show up in link authority metrics.

Well, you can't really optimize for broad match, because broad match includes synonyms  of your keyword, similar ideas, etc. Broad is very broad. I don't think there is ever a situation where it makes sense to optimize for broad because you just don't know what "broad" is.

Google's broad match is meant to give Adwords users an estimate of the volume of traffic that is out there in a very broad meaning of the keyword that can exist in all sorts of uses, most of which are likely not to be your customer.

You have two options....

1.) Place the domains into the name of a trust or a dba just for the domains.  ( I can get a dba for my company for $10 where I live and it doesn't obligate me to do anything)

2.) Use a domain registrar like 1and1.com or dreamhost.com who offers free privacy.

Warrrantywise, unless you've made some substantial changes to your content it's unlikely that the content is the issue.

It's more likely that your competition is beating you up and even more likely that your link builder is building links in a manner and rate that is making Google suspicious.