I was actually really excited to hear about cool properties to moves that I might not have known... : (
Peacocks cMK will trip airborne opponents. Only real time I've found it remotely reliable is as a counter to a Fortune attempting to overhead rekka.
Road Roller is an overhead hitgrab, as such it will ignore armor and cannot hit assist characters. It also counts as an "Avery" move. While it will make an Avery projectile disappear like other Avery attacks, it still has a chance of dropping if Peacock is currently in another animation with Avery in it anyway such as jMK, sHK, cHP, cLK, and Argus Agony.
Given Tommy 10-Ton's passive role (compared to Andy Anvil), in conjunction with a scrapped Peacock super in which Andy conducts a train with Tommy's face on it and then drive over the opponent, as well as similar eye shape, it can be inferred that the steamroller itself is Tommy after having transformed. If Tommy transforming into a vehicle is a retconned ability, then it's just a steamroller with eyeballs. That's something that Alex would need to clarify really.
Peacock's design document has her with a gaping hole in her back. This is presumably a hidden entry to hammerspace as a means of explaining how she can pull anything in her arsenal out from behind her (from the player's perspective).
Despite having rockets in her feet, she never really uses them for any attacks. An old sketch shows what appears to be a WIP sHK, but instead she sticks her foot in the opponent's face and lets the thrusters blast them.
I dunno. Are you happy now, senpai?