Hi,
This is a Yes and No situation.
iChat 6 as you say support Jabber (which includes the Google server), and AIM like the earlier versions of iChat plus Yahoo has been added.
Any Apple ID issued by Apple will work.
These are the @me.com (if linked to iCloud) the @mac.com ones from some time back (And include Lapsed accounts, Trial Accounts and ones that were paid for up to the the time MobileMe stopped).
It now covers the @icloud.com ones even though they are not listed in the Set up of iChat 6 as iCloud was not around back then.
You add the account as it it were an AIM one.
This is because these types of Apple ID are Valid AIM Screen Names. (it is from a 15+ year agreement with AIM)
There is one catch.
The Security process to login to AIM and Apple to verify the account needs iChat 6 to be at the last version.
This means the OS X has to be at OS X 10.7.2 at least.
This "Dual Login also applies in all version of Messages that follow iChat 6 and Lion.
As for the Messages use of an Apple ID as the iMessages Account the answer is no.
For that you would have to Upgrade the OS X.
That may also depend on what versions of the OS your computer can run.
8:44 pm Friday; February 12, 2016
iMac 2.5Ghz i5 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad