My big question is, if the "real" Sister Lucia died naturally, why not just say so?

So, I've posted about this matter before.  That's actually very important, and in investigating all crimes, police generally must come up with a convincing MOTIVE for the crime.

Why go to all this trouble?  Even if she had been murdered, or not died naturally ... WHY ROLL OUT THE FAKE? ... and risk getting caught.  Of course they probably felt there was much less risk back then, and didn't envision the days of the internet where just about anyone with a keyboard and internet connection could play amateur sleuth and find out all kinds of things.  If people think they can hide their pasts and secrets anymore as public people, they're deluded.  But back then they probably thought they could get away with it.

But even then, even with less perceived risk, WHY would they go to the trouble of rolling out the fake?

Answering this is where things take a diabolical turn.

As to WHY they would want to get rid of her, that's one question, and then WHY they would want to roll out an imposter a second.

First is easier to address.  Sister Lucia clearly indicated that the Third Secret had to do with something that would become clearer in 1960 ... obviously Vatican II and, IMO, the series of Conciliar Anti-Popes.  Cardinal Ciappi said it had to do with an apostasy that would begin at the top (aka with the Pope), and Father Amorth said Padre Pio told him that the Secret referred to Satan coming to rule a false Church.

Now, you could try to just shut her up by imposing strict cloister on her and forbid all to see her.  But of course people would start asking questions, and keep pressuring and pressuring and pressuring the Vatican.

So, then, if you believe these men to be evil enough ... they could simply kill her.  We're not sure they did this, and the Dimond Brothers relate how someone contacted them with information that they had killed her (a fascinating tidbit even if impossible to prove), or perhaps she did just die of natural causes, as Our Lady would take her from this world rather than giving her little choice but to attend the New Mass, etc.

But if she didn't die, they could kill her, or else they could disappear her very far away where nobody would find her, and just tell everyone she had died.  That would silence her and no more threat that she'd talk.

So, silencing her is insufficient explanation for why they'd roll out a double.

If they wanted to issue fake statements in her name, that's easy enough, and they appear to have done a couple of those also.  "Yes, Wojtyla properly consecrated Russia." or "No, the Third Secret has nothing to do with Vatican II."  "Vatican II is wonderful and Our Lady was pleased with it."

They could have stopped there, but too many people would have remained skeptical.  BUT ... if you see a smiling Sister Lucia standing next to Montini the Sodomite or nodding her head in agreement when Wojtyla releases a fake Third Secret, well, that's enough to convinced 99.9% of all Catholics.

Well, Vatican II and the New Mass can't be all that bad, as these Traditionalists say, since Our Lady's messenger clearly had no problems with it, assisting at this Mass, nor with the Conciliar Anti-Popes, implying her approval with her big smiles.

They felt the need to be THAT convincing, which they could only accomplish by rolling out the fake.

So, at the end of the day, this is simply more evidence that there's something in the Third Secret that they really don't like, and most probably exposes their evils.  That's really the only reason that makes sense and provides adequate motive for rolling out an imposter.