It seems that we need more characters/suits to take into account who is who.

I believe that the DOMs that we've seen Lacus building can be symbolized as well. I believe they'll represent rooks. I lack the knowledge of the DOMs from previous Gundam series but from what I see of their design and the various parodies in other anime, I think they suit the role of rook. I have 2 reasons.
1) Look at the head of the suit. Doesn't it look like a castle top?
2) Don't they glide or something when charging on land? (Last DOM I saw was in a recent eps of Yakitate! Japan)