>>>>Just for the OP sake (and mine) I think we can we expect the beat buyer to obtain the license.<<<<
IF you state that in your contract from the get-go and make sure that you are indemnified from any infringement issues; and of course nothing is a guarantee-- when there is a lawsuit, then there is usually an effort to "grape-shot" a net to sue anyone and everyone involved, and see what sticks...
I'll have to read the article to know what they are talking about, U.D. In general, it's best to avoid copyright infringement at all costs.
In the US (with similar laws in place in the UK, Australia, and Europe), copyright can be filed for a "song" (piece of music, whether it has lyrics or not), and only the melody, and any lyrics, will be covered, as BC said. For that, you file Form PA with the Library of Congress. For a "sound recording" (as BC said, you can't really copyright chords or an arrangement style on its own), which would cover the actual sounds embodied in that particular recorded version, you file Form SR (and afaik, Form SR can be used to cover both song and recording in a pinch, if the owner of both is one and the same, i.e., the scenario isn't a songwriter, artist, and record label that are all three different entities).
BTW, any intellectual property that you create is automatically protected by "copyright," the concept that you own your own creations (in absence of any other outstanding agreement, at least for some certain set amount of time)-- all you have to do is make a physical copy somehow (file on USB, CD, cassette tape, LP, 45, hard-drive, DVD, Blu-Ray, etc., etc.) and affix the (c) symbol and the year of creation. But because of the murkiness BC mentioned, and the international nature of releasing songs in today's world market, it is always best practice to ensure that your copyright is on-file with an established claim verification agency-- in the US it is the Library of Congress. This makes it a lot easier for you to prove infringement if a case ever has to go to court.
Also, it's confusing, I know, but once a song has been recorded and released to the public in some form (an official release, not a burned CD copy lent to a friend), anyone can do a cover version of the song, provided they obtain a license. Under US Copyright law, a license is compulsory, i.e., as long as someone files in good faith with an agency like Harry Fox or Limelight and pays a set fee, they can cover and release that song (again, after a first release by the original owner and/or licensee as in the record label). So I can do a whole double album of Rolling Stones covers, if I have paid for the privilege.
This right is completely separate from borrowing melody for a new composition, adding/re-arranging an existing piece (called a "derivative work"), sampling (a complete and whole 'nuther ball game), doing a re-mix, licensing for film, television, or musical theater use ("Grand Rights"), digital release rights, or any of those other related, but different side issues (all covered under different portions of US law and various international laws and agreements).
Copyright is huge business, which is why it is an area that many attorneys specialize in-- there is a lot of $$$$ involved.
So no, it's not a simple thing, and I would rather write something original than go around borrowing melodies from others ad hoc/unadvisedly...
GJ
Disclaimer-- NOT an attorney or barrister, so seek legal counsel. There are a number of sources in print and on-line that can help you get a better grip (and a more accurate one) on the basics of copyright law. I would start with the incredible primer by Donald Passman ("Everything You Always Wanted to Know about the Music Business..."), which gets into quite a bit of the nitty gritty of song copyright and dealing with labels. It helped me out a lot as a songwriter, recording artist, and having my own label (sometimes licensing songs or previous recordings for compilations, sometimes releasing original work). You can also find out a lot by checking-out the ASCAP and BMI websites, the Harry Fox website, and the Library of Congress copyright section.