I'll be interested to read the details, but 2 out of the 3 things have been known for quite some time. The 'caller ID' spoofing trick has been known for _years_. The concept they are touting is known as "back spoofing". I've had friends doing this for a long time. However - there's one problem. No call cell phone associate caller ID with a phone. Yes, back spoofing works great - with _land lines_, but it's always that accurate with cell phones. So, "finding" the cell number that way isn't very reliable. If I have a boost mobile number, bought in cash, under a fake name you'll be out of luck. That is, the caller ID name (CNAM) won't be associated with it in the first place _and_ I gave all fake information to begin with.
About the voice mail. Not a big deal. This was reported 6 or more years ago. The idea is that you spoof your targets number with their cell number. The Telco side "sees" this as a call from the cell and drops you into their voicemail system. Some telco's have fixed this, other haven't. It's been a known flaw for years and years. You don't use CID for authentication exactly for this reason.
If possible, PIN protect your voicemail will stop these types of attacks (if possible). Anyways, the article is interesting, but several factors must fall into place or this attack won't work.