The pictures are not showing up (presumably caught in the anti spam filters) but is "I seem to have enabled GBA mode with the GBC color palette" a bad thing?
Most times we see this then forcing GBA extras is good and all but any palette changes to work with the original GBA screen are not desirable. From the wording there then you sound like you have the best of both worlds right off the hop.
For others playing along at home then GBC games could detect if they were running on a GBA. As the GBA was new and exciting then a handful* of games added bonuses for running on one. Some of said games also tweaked the colour palette to be more appealing on the awful original GBA screen, if you see it on something else (like a GBA SP, never mind the AGS 101 line of GBA SP) it will tend to appear washed out and not good.http://bgb.bircd.org/pandocs.htm#cgbregisters
The classic check is a soon after boot that will be checked and then noted, any additional unlocks made available accordingly. Said things may also be used to alter the palettes ( http://bgb.bircd.org/pandocs.htm#lcdcolorpalettescgbonly
) so you might have to find the thing that checks for this and alters colours, or set the thing that provides extras to always have them while maybe not doing the colours at all.
*Shantae, as well as the Zelda titles Oracle of Ages and Oracle of Seasons being the main examples people look at.