Okay first - superlative work, guys!
Second, having had a fair crack now (start to Lady Deathstrike), I have noticed the following. Bear in mind that it might be something at my end, since I'm not very used to doing this sort of thing!
Despite apparently following the instructions in the readme (i.e. copying the 15101.IGB from the Menu Portait folder from the zip (as opposed to the 15101.igb in the HUD folder) to the XML2\UI\models\characters\ folder, I don't appear to have a selection picture in the team setup screen.
Second, the Energy Blasts are coming out a bit odd - the trails appear to be coming out sideways; perpendicular to the line of flight - to the right, I think - not in line. (They don't appear to be making any noise, but I gather editing sound is not possible at this stage).
Other than that (and the fact that when I tried hex-modifying my older saves game and it crashed flat out every time) it has been running as smoothly as you like!
Is there, by any chance, a Jubilee mod as good as this from Ultimate Alliance yet?