Symonds is definitely in the discussion for an AT XI, generally batting at 7. Whether he's there or not depends on the other players you pick and the role you need. If you're picking a side for the subcontinent he absolutely should be in the reckoning with his handly offies, rope clearing ability and ridiculous fielding. He's basically competing against Klusener for a spot in an AT XI, but a lot of people include Jayasuriya in an AT XI, which means you might not need Klusener's superior bowling and might go for Symonds' batting and fielding instead (Symonds was a better bat than Klusener, 99 WC notwithstanding).
Certainly Symonds isn't a lock, but he's by no means out of the conversation.
Watson I feel was very good but as an opener was one of many that could fill the roll with the bat just as well, and as a bowler wasn't as good as other options (e.g. Klusener). I'm not even sure I'd have Watson in an Australian XI. Let me think about this a bit.
Australian XI options:
Openers
Gilchrist, M Waugh, Hayden, Watson, Warner, Boon, Finch
Middle order batsmen
Ponting, Bevan, Jones, Clarke, Hussey, Smith, Martyn, S Waugh, Border, G Chappell, Lehmann
All rounders
Watson, Symonds, Faulkner, S Waugh
Bowlers
McGrath, Warne, Starc, Lee, Lillee, Bracken, Johnson, McDermott
Which leaves us with:
Gilchrist
M Waugh/Watson/Hayden
Ponting
Jones
Symonds
Bevan
Watson/Hussey/Faulkner
Starc
Warne
Lillee/Lee/Bracken
McGrath
Looking over those options I personally would have Watson bat 7. He was more suited to the top order but at the same time, Gilchrist + Waugh were better openers, Ponting, Jones, Symonds and Bevan all basically pick themselves for those batting positions with S Waugh and G Chappell the only other real option for batting 5. Symonds is the 5th highest run scorer in history batting at 5 behind Ranatunga, Waugh, Shakib and Inzi and is tied third behind Yuvraj and De Villiers for hundreds scored in that position.
So Watson is fighting Hussey and Faulkner for the Aussie AT number 7 slot IMO. I think Waugh was significantly better as an opener and the Australian AT 3-6 pick themselves.