Well there is a bit of news on the forms, it is not confirmed but it looks like the most probable. So from what the source says the three slots in the new driver will be used for head, torso and legs. The animal medallions are divided in that order.
Head medallions consist of the Taka (Hawk), the Kuwagata (Stag Beetle) and the Shishi (Lion).
Body medallions consist of the Washi (Eagle), the Kamatari (Mantis) and the Tora (Tiger).
Lastly the leg medallions consist of the Karas (Crow), the Batta (Grasshopper) and the Chita (Cheetah).
The birds are colored red, the bugs are colored green and the cats are yellow.
The main form is the Taka, the Tora and the Batta which is supposedly named ToTaBa or more sensibly TaToBa. With this, we can say that they take their first two letters of each body section animal and put them together. He will have a full red, green and yellow combo naming is obvious. Now if they are capable of making more combinations and if we do the math that is 27 combinations. This could mean a lot of figures and toys...
Source: http://henshinjustice.com/forums/showpost.php?p=1007724&postcount=1488
