Problem is same team for 3 formats so allrounders can't be ignored.
Mixed XI
First lets isolate absolute musthaves
Bradman
Sobers
Richards
Tendulkar
Gilchrist
Warne
Akram
Mcgrath
Then marshall for me
Imran for balance and fifth strike bowler.
Tendulkar and gilchrist open in odis and t20.
Main problem is opener for tests i'll go hayden since he's relevant in all formats.
Hayden and gilchrist open in tests,bradman 3rd sachin 4rth,richards 5th,sobers 6,imran 7,marshall 8,wasim 9,warne 10.mcgrath 11.
So final XI
Batsmen -
Bradman
Tendulkar
Richards
Hayden
Allrounders -
Imran[c]
Gilchrist[wk]
Sobers
Bowlers-
Marshall
Wasim
Warne
Mcgrath
Ground - The WACA ,perth since bowling attack is pace based and all batsmen are excellent players of fast bowling except hayden[swing] maybe but thats less of a concern in odis and t20s,plus its his home country so waca.
Scenario 2 -
Ground - Firoz shah kotla dustbowl,or wankhede mumbai dustbowl or premedasa sticky minefield.
Team
Sehwag for hayden.[home conditions,no swing]
Kumble and murali in for marshall and mcgrath.
Wasim and imran stay because of ability to use reverse swing with old ball and familiarity with subcontinent conditions.
If seperate teams for formats
ODIS
Tendulkar
Gilchrist
Ponting
Lara
Richards
Bevan
Imran[c]
Garner
Akram
Warne
Mcgrath
Tests
Len hutton
Sunil gavaskar
Don Bradman[C]
Sachin Tendulkar
Viv richards
Sobers
Gilchrist.[wk]
Warne
Marshall
Ambrose
Akram
12th man-D.lillee
Akram over lillee due to deadlier old ball with reverse swing.
Ambrose and marshall walk into test sides imo.
No coach.Can't see anyone telling these guys what to do.