Right after the text it says: Actually, this is a joke. If you happen to be a real, serious fan of Agnetha Fältskog (and I'm not, I'm just an ABBA fan) you can take a look at another site. www.frojmark.net/hammarlund/texter/agnethae.htm
The text is also published in Swedish, his native language, where he also says it's all a joke.
The guy's website www.frojmark.net/hammarlund/ is filled with texts that he's written, all in the same "humorous", ironic and non-serious way.
SO - this IS a joke and nothing more! It can't be any clearer than that. Fact is fact.
If you still want to speculate about the whole ABBA being repleced (but they were not IMO) you're free to do so. But please do it without leaning on texts that was written as a joke! Always check your sources, it's very important, especially while dealing with this topic.
Also always ask yourself "why?" "what would be the reason?" In ABBA's case I can see no purpose for a replacement. And again, no one of the ABBA's has had any change in personality etc which is key when someone is replaced by a double. And if they were replaced by clones - well, then we would hardly know anyway... but they certainly don't have that "plastic" and "new" look about them that IMO is characteristic for clones.
They also replace people with doubles. For many years they recruited look-alikes who would serve their ends. Now they are perfecting cloning technology that will let them replace anybody. (The Illuminati by Abner Whateley)
Agnetha and the crippling fear that means Abba will never reunite: How one of pop music's most iconic sex symbols left fame in favour of a reclusive life with her dogs
To be fair, it wasn't exactly the billion- dollar reunion fans had been dreaming of. Last Sunday night, at a private party in a function room at a Stockholm hotel, all four members of Abba took to the stage and created a moment in musical history.
They'd intended to share a few stories and anecdotes with their audience, on the 50th anniversary of when the two male songwriters met.
At one point, Agnetha (the blonde one) and Anni-Frid (the brunette) started to read out some lyrics to one of their rather lesser-known songs. Then Benny and Bjorn surprised everyone by starting to sing along.
In the end all four sang, albeit briefly. It was a moment Abba devotees had been waiting many, many years for.
There was no band, no publicity and, crucially, no recording. Just a few fuzzy photos confirmed this most unlikely event had occurred. But even the idea of it was enough to send social media into a frenzy.