Hey there. Just sharing a possible idea I thought of, but don't have the time and energy to do myself. However, anybody who likes the idea enough CAN tackle it:

In this universe, Thorax (who, in this universe, ran away from Chrysalis's hive more than two decades sooner than in canon) and Cadance met VERY shortly after the latter ascended (but WELL before Cadance met Shining Armor) and, well, started out as friends. However, they gradually got closer over a period of years, to the point that, by the time Shining Armor and Cadance finally met, she was already romantically serious with Thorax and Shiny just couldn't compete.

Thus, though Shining Armor had a huge (and insultingly obvious) crush on her, it was doomed to be forever one-sided. Because of this, by the time he entered the Royal Guard Academy, he basically buried himself completely in his studies (and, when he graduated, his duties). Ultimately, Shiny ended up becoming the bodyguard of Princess Celestia's personal student - his own little sister. This was a duty he took EXTRA seriously (in fact, SO seriously that he even turned down several chances at promotion just to keep doing it).

Ultimately, Shining Armor, along with Twilight and Spike, went along to Ponyville to oversee the 1000th Summer Sun Celebration. Along the way, they met - among other ponies - Applejack and her brother Big Mac as well as Fluttershy and HER brother Zephyr Breeze (yeah, they also met Rainbow Dash, Pinkie Pie and Rarity [which is why I SAID "'among other ponies'"])

Anyway, when Nightmare Moon returned, Rainbow Dash got pretty badly injured in Nightmare Moon's initial attack (Zephyr got REALLY steamed about THAT, but Fluttershy, Mac and Applejack calmed him down enough to stop him from doing anything rash). Anyway, after making sure Rainbow made it to the hospital all right (and entrusting Pinkie and Rarity to watch over Rainbow and let them know when she was going to make a full recovery), Fluttershy and Zephyr joined the others on their journey to stop Nightmare Moon.

Anyway, the Elements boil down to this:

Magic: Twilight

Loyalty: Shining Armor (he got THIS Element in the rockslide by insistingly using his magic to gently lower his sister down to the ground BEFORE he was saved)

Honesty: Applejack (she got this one during the "Fear Trees" trial by seeing through Nightmare Moon's illusions with truthful observations)

Kindness: Big Mac (by showing compassion to a sea serpent in distress)

Generosity: Fluttershy (because of how far she will go to help even animals that most ponies would understandably prefer to avoid [for example, she not only removes the thorn from the paw of a Manticore, she also gives the part of the paw the thorn was in good-quality first aid])

Laughter: Zephyr Breeze (showing a flair for creative problem solving AND for utterly MOCKING Nightmare Moon's rather pathetic attempt at temptation at the bridge [for example, pointing out that "Hello? mysterious shadowy figures at a bridge offering you something you want in exchange for abandoning your sister and her friends with the fate of the world at stake? Seriously? Only somebody who was both a complete jerk AND a complete idiot would fall for it and not even *I* am THAT big a jerk OR that stupid)

So, yes, Zephyr DOES get a bit of Adaptional Intelligence AND Adaptional Heroism in this story in order to make him more tolerable as an Element Bearer. Unfortunately, it was the only way I could think of to make the "Brotherverse" idea work

And, anyway, as for Cadance and Thorax, well, Cadance's influence makes Thorax MUCH stronger (not JUST in terms of physical and magical ability granted from love voluntarily shared by the Alicorn of Love herself, but ALSO in sense of developing a real backbone without losing the niceness) and the two end up overthrowing Chrysalis more than three years BEFORE the Royal Wedding (in this case, Cadance is still the bride, but Thorax is the groom). Meaning that Thorax and Cadance end up eventually becoming King and Queen of Chrysalis's former hive and, when the Crystal Empire returns and Sombra is defeated, the Changelings of Thorax's hive end up becoming part of the Crystal Empire's honor guard.

Unfortunately, while I was able think of all of this, I was NOT able to think of enough "in-between" details to make the story idea work.

But anybody who likes the idea can adopt it and try their luck.