Why are the chances of that happening "undeniably low"?
So, i don't know precise chances of this happening, but it us obiviously low. Look, lets assume planet gravities can be a 0.1 m/sē higher and lower. This will require little less or little more of matter, so we aren't breaking any Early solar system simulations of quantaty of gas form which we formed.
Gravities match with one decimal digit of accuracy so we are going to go with that.
So imagine you had dices with 20 (representing 0.1 m/sē more and less) sides, and you needed to roll them to match. After some time you will get it. Nice, you have one pair of planets, but what about second pair? Do the same thing, but with both sets if dices, since we are calculating chances of it both happening in same systems (you don't need to have same number on both dices, for example 6-6 and 18-18 will work.)
And this is only when we are using 0.1 m/sē change of gravity...
Chances are low. Our solar system has some odd things. Like intensity of sun bieng 6.66 higher on mercury than Earth, and mars Aphelion bieng 1.66 AU, and this...
They like to put hidden messages in solar system