my first reaction to swapping in Item was to hold my nose when reading this months back. you already acknowledged how that's fudgy, so i won't harass you on it.
i was holding comments until testing. my main concerns were getting different results on monster command counters. Palidor mostly dodges this, with the actual attack done via a separate Jump command. it took testing vanilla to refresh me on this; i guess that examining Slot ==> Item ==> second item strike for summon ==> extra turn was enough to make my brain overheat. now, other summons (when Muddled if they target the party, so that includes the initial part of Palidor) could cause an issue in theory, but turns out no enemies counter Slot or general Item commands. and Muddle+Palidor is a giant can of bugs and worms anyway -- straight out of a bait shop from Hell -- so worrying about "proper" counter behavior there is overshadowed some.
still, a disclaimer about command counters might be worthwhile.
or it'd be nice if there was a way to add a little code to only Item-ize the two summons that actually have the graphical bugs, but that'd involve a semi-persistent free RAM variable, at the least.
now for actually looking at the code.
C2E715: ASL A
C2E716: TRB $11A9 ; remove Magicite's special effect
why not "STZ $11A9"? it's not like that variable is a bitfield with multiple special effects at once. sure, it's just one extra byte, but also weird to follow.
C2E727: CMP #$01 ; Item?
C2E729: BNE exit ; if not, exit
can change to "DEC / BNE" for another 1-byte gain, but without coherency improvement of above idea.
a more involved change i have in mind is: rely on the Magicite Item's second "strike" to do what's needed in C2/3666. the first "strike" would have you skip the function call (or exit after restoring Bit 0 of $B2) when your Slot+Magicite is detected. no urgency to it; just smaller code, and less alteration from vanilla. more than anything, i'm curious whether it'd work.
We have EVEN MORE themes now, but some old ones are gone...