I thought it would be good to do a comparison of the Event Exclusives (and/or Limited Editions) to their Regular store counterparts. I do have some comparisons on the 'Itty Bitty Basics' page and notes to identify the different versions on the index pages. I just thought it would be fun to look the differences between them with a little more detail! Event Exclusives (or Limited Editions) will be on the left side and the Regular version will be on the right. (With the exception of Han who only has a Event and Limited versions)
  I am looking at the detail on the actual itty bittys. In all cases the tags between the two versions are different. Also the Event Exclusives have the round label (normally on the bottom of the itty bitty) stating the event and year they are from. I won't really be listing these in the differences in the post.
Boba Fett    Event Exclusive/Regular 
Antenna                      White/Grey
Helmet Hash Marks   Yellow/Red
Belt Detail                      Yes/No
Armor detail    Breast Plate hash marks/Helmet round mark
Bracers                      Green/Red 
Jet Pack                    Green/Red&Yellow
 
Sorry about the color differences in the picture, they really aren't that much different. 
|  | 
| Event Exclusive and Regular | 
 | 
 | 
Rainbow Brite  Limited Edition/Regular 
Star on cheek color          Blue/Purple
Bottom                            Plush/Shiny red
Bottom strips      Yellow stripes/Green stripe
Regular version also has green in the rainbow logo on her chest.
|  | 
| Limited Edition and Regular | 
Twink           Limited Edition/Regular
Star on Belt        Yellow/Blue
Pouch on Belt       Red/Orange
Bottom Stripes     Finer/Green Stripe
Bottom                Plush/Shiny 
Eyebrows              No/Yes
|  | 
| Limited Edition and Regular | 
Sprites   Limited Edition/Regular
Bottom                Plush/Shiny 
Eyebrows              No/Yes
|  | 
| Limited Edition top row. Regular bottom row. | 
Swimsuit Barbie         Event/Regular 
Hair Color            Brunette/Blond
Bathing Suit   Embroidered/Printed  
 Sorry about the eye shadow, I know it looks grey on the Event one in the picture, but the actual itty bitty has blue. 
|  | 
| Event and Regular | 
Han in Carbonite  Event Exclusive/Limited Edition
Texture material                 Plush/Shiny and smooth
|  | 
| Event Exclusive and Limited Edition | 
Kylo Ren   Limited Edition/Regular
Lightsaber                  Yes/No
|  | 
| Limited Edition and Regular | 
 | 
Belle (Yellow dress) Limited Edition/Regular(2nd in Series)
 Detail                         Embroidered/Printed
Color Variation                         No/Yes
NOTE: Once the second Belle is released we will have a better idea of the differences and I will update this.
|  | 
| Limited Edition and Regular | 
Holiday Barbie         Event/Regular
Bottom writing color  Pink/Red
There
 isn't really any difference between the two other than the color of the
 word 'Barbie' on the bottoms. See picture comparison on the 'Itty Bitty
 Basics' page.
 There are also Event Exclusives (like the Holiday Barbie) with no real differences between the Event and Regular version. These include the event Batman, Darth Vader, and Batman & Superman clippy. They don't vary from their store versions other than the tag and bottom labels.
(Superman, Batman)  Storybook/Regular 
Body                             Printed/Plush
Glinda   Storybook/Limited Edition
Skirt             Shiny/Tulle
Dorothy   Storybook/Regular
Mini Toto           Yes/No