I'm not sure why you'd treat mind/int's effect on spell potency as some sort of separate modifier. It's inherent in what they provide as a stat. Internal Release/Blood for Blood stack on top of the finished weapon damage + main stat calculations however, meaning that their potency is far more effective with better weapons/gear (to the point that thinking 20 int would be better is laughable).
Creationists denying evolution like to use this same argument when dealing with overwhelming evidence. Bravo.
Yeah. You haven't done your research on this shit at all, and it shows.
Allagan Scepter - Item - Final Fantasy XIV : A Realm Reborn (FFXIV ARR) Database- provides 26 accuracy.
Ancient Buckler - Item - Final Fantasy XIV : A Realm Reborn (FFXIV ARR) Database- provides 11 accuracy
Lava Toad Legs - Item - Final Fantasy XIV : A Realm Reborn (FFXIV ARR) Database- provides 27 accuracy
Not even sure the legs would be needed, but the combination of the 3 provides exactly the same amount of accuracy that the full BLM myth set does. So no, you wouldn't have to mix and match at all. You also wouldn't have to wear any darklight jewelry, because none of the myth jewelry (or belt) has a class restriction.
Again its just pure theorycrafting.
Example I have 112 acc atm from gear alone, have a total of 453(still about 20ish from cap).
Full allagan only gives 103 from gear.
Now there is some other stat or something giving the extra Acc to make the jump from gear => stat, but no clue what it is, its not int, because you can take a peice off and you just lose the Acc stat only. So i assume its static and doesn't' change.
Now to add food, your lava leg leg is a dumb choice, because its 3% to get the 27, which takes a monstrous 730ish accuracy to gain(and if we do 3% of say 444, 9 less then what I have now based on full allagan Acc, its only 13 Acc, so still a bad choice no matter what) . No the food you use is the cabbage which gives 17 accuracy and only takes 420ish to get that max. So we have 444 Acc(my current acc minus the 9 Acc from going full allagan) + 17, so 461(still 10ish from the supposed cap, which is reported to be around 470-475).
Whereas I could mix and match gear I could get 152 Acc from gear, which would give me 493 Acc, about 20 over cap, so I can now either drop a gear peice or two and pick up dps stats and I can also use DPS food like buttons in a blanket etc.
Again its all pure theory because there are no solid numbers to back it up and I'm not dumb to make a statement like ,will full Allagan THM is top dps in the game, as fact without it.
Ability wise I am not sure, I guess it depends on future content, but atm I do use flare, convert, manawall and apoc.