hmm, well, you can also create blaze rods using a gregtech uu matter recipe, and you can get a matter fabricator with power and scrap without using blaze rods, the only things you can exclusively obtain using the minium stone, unless you travel to another age, are the spruce and jungle saplings and melons, which can be miniumed using a pumpkin, which you can get from a scrap box, and basalt cobblestone. So it depends how hardcore you want to make the map, or if you allow the player to create another age to get some items which cannot be gotten from the overworld, or just vendor said items and then you technically wont have to use the minium stone to obtain things
Oh and you might want to add marble and basalt cobble and maybe red cobble( in exchange for clay) and such things to a vendor, so that we can make our bases, or whatever, a little bit more appealing, since those blocks don't have that much of a function, as in obtaining items early on
And is there a way to obtain any iridium, because i havent found one yet, and if I'm not mistaken, you need iridium to create the matter fabricator?