Quick update: So, I've had a look at the ESM files in GECK, and from what I can tell, the missing files are referenced in the BSA files in the following manner:
Caravan Pack, Lightweight Leather Armor, Male: NVDLCPre3\Armor\preordLeather\preordLeatherArmor.N IF
(Mesh) NVDLCPre3\interface\icons\pipboyimages\apparel\app arel_lightweight_leather_armor.dds
When I initially extracted the BSA archive for CARAVANPACK - MAIN.BSA, the folder structure extracted as \meshes\nvdlcpre3\armor\preordleather\preordleathe rarmor.nif
and \textures\nvdlcprere3\interface\icons\pipboyimages \apparel\apparel_lightweight_leather_armor.dds
Now here's where I'm at in terms of progress: I am unsure if the PS3 version of the game is case sensitive when it comes to file paths, not to mention the ESM doesn't specify neither the \Meshes nor \Textures folder (see the below screenshot) in the file path, as they directly reference the NVDLCPre3 as root. Again, GECK/Fallout 3 modding is somewhat new to me, so if anyone out there is versed in Fallout 3 modding and ESM/BSA editing, I'd greatly appreciate any assistance you could render.
Anyways, to make this post worth reading, here are some screenshots of my progress, showing where the items from the DLC are loaded and displayed in the PIPboy, and also showing where the icons and meshes are missing ingame. Babysteps, but progress is progress
Here are some screenshots of my progress. I tried posting them in the post with descriptions, but because of the new way attachments are dealt with, I've had to attach them to the post instead. They're pretty self explanatory anyways
Note that while the shotgun may not appear ingame, it does in fact still fire, so the only issue seems to be a filepath issue to the meshes/textures/icons.