OK, some useful information there.
For those who are interested:
An Xbox trainer for BF2 is here at Maxconsole.
Basic trainer features, some of them fun to play with.
Hex editing of lvl files is discussed here at Scenyx,
with some hero swaps and weapon swaps between units. It turns out the lvl files have many human-readable strings, which makes certain things not difficult to edit, with the usual hex constraints on space for data.
Mission.lvl files for PC BF2 mods work with for the Xbox, subject to limitations I haven't fully explored. For example, I haven't tried playing custom maps or altered skins. I've played a PC mod consisting of Yoda and Obi Wan as units against Anakin (as a unit) and clones on Coruscant. Not a great mod, but it worked without a hitch on the Xbox.
So it seems the output of the Mod Tools is compatible with Xbox, at least in some cases. If some of the simple mods I want "require" a remunge, then I just need to get BF2 for PC, perform the remunge, and upload to the Xbox. A comparison of the lvl files before and after remunge would reveal the corresponding hex addresses. I'll post my findings here for posterity.