Honestly, I don't really know about the 360 degree free battle camera, because I don't use it. I tend to try to slog through battles in 2~3 turns so I didn't have much need for it. However, I'm assuming you're referring to this program:
http://forum.1cpublishing.eu/showthread.php?t=16803
The guy says for CW, you should add a line to your "game.ini" file (should be inside your /data folder.) Have you done this? I'm unclear whether this line needs to be added if you're playing CW, or if you've simply just installed CW.
As for buying the original AP and playing that - I'm not sure. I'll have to let someone else answer that, but I'm fairly certain that there will be no difference. CW isn't its own game, it's "Armored Princess plus Bonuses." For me, when I load my version of Crossworlds from Steam, I get to a "main menu" where I can select to play Armored Princess, Champion of the Arena, Defender of the Crown, and Orcs on the March.
Of these, "Armored Princess" will load the original game. "Champions of the Arena" and "Defender of the Crown" as far as I can tell are not actual campaigns, but miniature gauntlet-type quests. "Orcs on the March" is the Crossworlds content, and this should (as I've read) load the same exact campaign as "Armored Princess" except you get the nifty bonuses (along with an orc on the first island that gives you the extra quest, creatively titled "Red Scrounger and the March of the Orcs.")
Once again, I don't really know how that free battle cam works, so I can't help you much there besides maybe checking the game.ini file. I've only played CW (Orcs on the March) because people said if played AP first, I'd have to repeat everything for OotM.
However, I can say definitely that CW and AP load mods from different folders. I originally placed mods in the AP folder (when I was playing CW) and they wouldn't work. I moved them to the CW folder and now I'm running a bunch of mods, such as:
Contract Heroes Marker
Camera Mod *NOT the free camera thing you're referring to; this one only allows further zooming on world map
Interface Mod
Pet Hint Mod
As well as a couple mods I created to modify the treasure chests, fixing a few skills/items, and tweaking a few other things.