I have never had success in getting a link from or even an idea picked up by/through HARO. And I do think that I have offered some useful tidbits, etc, but there are a lot of others offering useful info, too.  The service is probably more effective for journalists than for SEOs or webmasters. I  am US based.

No reason too worry, as others have said. I  don't advise nollow, actually - in general, I believe comments should be moderated; if they are spammy they'll never be followed because they won't be approved. But a clearly stated moderation policy that lets readers know that substantive comments are appreciate - and rewarded with a followed link - encourages good contribution, IMO.

It shouldn't; search engines can isolate strings without separators. However, how many people do you think actually type 'girls pink yoga capri' or are you just being hypothetical?

Matt Cutts recommends against using nofollow this way -- now, you might want to take anything Matt says with a grain of salt, but we do know that you cannot control the flow of PageRank in this way. Your other pages will not get more PR because you have nofollowed others; instead Matt says, the PR is lost. See the video

That said, a larger site might benefit indirectly from a judicious use of the robots.txt file to prevent the indexing pf pages that are not likely to end up in the SERPs and allowing more of the site's crawl time allotment for pages that have SERP value.

watch?v=4SAPUx4Beh8

Just in case you don't already have enough feedback: No, don't do it! The h1 is not the most powerful onpage element .. I think the title tag gets that award -- but it can be a useful factor. It should be written for the user - think newspaper headlines!

And just as each page should have distinct content, and a distinct tile, meta description, etc, so it should have a distinct, effective, h1 tag.