In answer to your question- Yes, technically an item can be Magecrafted(by using said specific very expensive World Magic) with the ability of any personal magic. However just because the item has the capacity doesn't mean it can use it, or that it can pass on its effect to the wielder.
However having a Magecrafted item have its personal magic effect constantly on would not work, since it'd quickly go into overgiving and never be able to stop. I'd also question the usefulless of a flaming sword, since it'd probably cauterize any wounds if it did work, and if it didn't it'd probably just ruin the blade.
In the example of your fire sword, it'd probably work once, then go into overgiving, and probably eventually explode or something from trying to continue to use magic into overgiving.
It seems though your kind of asking two questions here, one about the intellectual control of the item, and one about flux.
1- Intelligence- Yes, higher level items will have higher level intelligence, so that it can regulate and use the magic with more finesse. If you have the room for extra steps this is ideal, as not only does it make the item safer it also makes it that much more useful in that it can work in many different ways.
Much more common with lower level items is a single behavioral step, usually along with a single intelligence step. Behavioral steps can be used to hard wire a item, such as a Magecrafted item with use of personal magic, into doing a specific spell/usage of the magic. Its taught that specific thing, and thats all that it can do with the magic. No variation, no finesse. Usually then a single intelligence step is used to allow said hardwired behavior to be activated, turned on/off, etc.
This usually means less steps than if you'd given it a full fledged intelligence, which means cheaper, but also with less/no ability to vary its usage.
2- Flux- From what I've seen of Magecrafted items, they tend to work in one of two ways. Either outwardly, upon something else, such as that morphing shaving kit, or inwardly upon themselves, such as a sword that can shoot flames.
They can't work both ways. So I would imagine, logically, that the item would only work upon itself, or the wielder, not both, no skipping djed back and forth with some flux move or such.
2B- If you just want a conduit for your flux, you using it through it, a "Magic Staff" would work, which in and of itself is a particular Magecrafted enchantment upon a piece of once living material of a certain size. Its got its own lore page also which you might want to read. With that you could channel your flux in and through it, and other things said Magic Staff can do.
If you've got any other questions or need clarification I'll do my best to answer, though bearing in mind not everything has a specific answer.
Happy rping,
Clyde Sullins