Theory on those 8 or 7 missing items

[Ace Lancelotwarrior]

Since the rest of Sardine set comes from a iz maybe those 5 or 4 Ben 10 items come from lvl 12, 16, and 20 iz's. And the rex ones come from a lvl 15 iz. Can anyone check if their are iz lvls like these or are close to them?