I recently figured out how to get rid of the "Ready to Fight" bar. Editing the bones of the bar did not seem to work since its animation would return it to the original position. Editing the animation will get the job done. The file I provide below moves the bar 200 units in the Y direction, but any direction will do as long as it's a large enough translation.
1. Open sc_selcharacter.pac in BrawlBox
2. Expand MiscData 
3. Expand AnmChr(NW4R)
4. Download this: http://www.mediafire.com/download/zxaoqy20pzwxdgp/MenSelchrReady_TopN__X.chr0
(The Y Translations are set to 200 for each keyframe)
5. Right click MenSelchrReady_TopN__0, select replace, and replace it with the downloaded file
6. Repeat step 5 for MenSelchrReady_TopN__1, MenSelchrReady_TopN__2, and MenSelchrReady_TopN__3
Goodbye "Ready to Fight" bar that blocks the bottom row of Brawlex!