Could Milo craft magic items with wanded magic spells built in? The magic item creation rules state that a caster can create items that contain the effects of spells he can't cast, as long as he has the appropriate caster around to actually cast the spell

It likely wouldn’t work, because HP spells don’t have levels. As a result, trying to slot them into the established formula, which requires their level to calculate price, would throw up an error that could only be resolved by direct DM intervention. Milo doesn’t like pushing into territory where the DM has absolute say, and where Milo doesn’t have a solid argument to back up his side, because DMs are unpredictable and, in some cases, petty. Sure, it could work—but the DM might instead rule, for example, that now that he/she/it had really thought about it, Milo shouldn’t be able to make magic items using HP-world raw material at all.

As such, he’d only turn to such an option in the direst of circumstances.