I highly doubt any of AT&T's restrictions on apps would have applied/do apply to Apple. If Apple wanted to make an iChat app, they would've just gone to AT&T directly and worked with them on making sure the network could handle it and then do it.
Mentioning video chat would have been a handy detail.
ATT opening up to VOIP means nothing without a front-facing camera. You might be correct that they will wait for the ff cam before releasing a native iChat.