My first team for the World Cup at the moment would probably be:
Warner (pending good form in the IPL)
Khawaja
Smith (pending good form in the IPL)
Handscomb
Maxwell
Stoinis
Carey (wk)
Starc
Cummins
Zampa
Lyon/Hazlewood (depending on conditions)
Captaincy is a difficult one, probably give it to Khawaja or Carey with the other one of the two being the official vice-captain and Smith as the unofficial vice-captain.
A well selected team
@jap. IIRC there is another ODI series in the UAE before England?
I think a lot will come down to the English weather, and to some extent, the type of ball used in this World Cup.
The way England play ODI cricket these days: big tall batters hitting on the up, (mis-)hitting lots of sixes down the ground over really short boundaries, their game suits road pitches. And ironically, a White Kookaburra ball. They have a team suited to high scoring conditions.
If conditions are a bit more typically "English": slightly slow, but green and seaming, then that changes things, and ironically I think Australia will need those types of conditions to win this World Cup.
S Marsh has a poor record in English conditions, (in fact he has a poor record almost everywhere :--) ), as does Warner. But Marsh's white ball form in Australia this summer was undeniable.
If the pitches are green, I think Handscombe will be a predictable failure - out LBW. Unless he bats at #5 S Marsh will also make a string of low scores
I think the current selection panel has been too quick to reward players for one or two good performances, and too quick to punish for one or two bad ones. IMHO they also give too much weight to form in the alternate formats (though again IMHO good form in one format
does usually translates to good form in the others).
On that basis I think Turner is now a near certainty to be in the Aussie WC team at 6 or 7. However I think it is a good selection based on what I've seen in the BBL. Turner is a mostly orthodox bat who can also hit (and mis-hit) plenty of sixes, and has a high strike rate in most white ball cricket forms.
If England prepare roads for the WC (*and* the weather allows them to), we'll need both Turner and Maxwell firing.
If the pitches are green, we're going to need more orthodox cricketers to ensure we post a dependable total in conditions where our quicks can bowl a team out in 50 overs.
As for our spinner - Lyon is definitely a class above Zampa - or anyone else in Aussie cricket for that matter. But in modern ODI cricket the spinner needs an an "accurate" (by ODI standards

wrongun. Even England now regularly play a leg spinner ahead of a finger spinner for this reason. Given spots in the squad are limited, I'd be inclined to roll the dice and leave Lyon out altogether, and got with Boyce or Sweptson as out second spinner for turning tracks.
So this is
my high risk sqaud for the WC 2019 (assuming it's 15 players)
D Warner
U Khawaja (c) (this definitely *won't* happen)
S Marsh (Can't believe I'm doing this, I would much rather this be A Finch, but runs on the board are runs on the board)
S Smith
T Head
A Turner
P Handscombe (wk) ... this is a big risk !!!
G Maxwell
P Cummins (vc)
J Berrandorf
J Richardson
M Starc
A Zampa
C Boyce (Fawad Ahmed is very unlucky I'm not opposed to being ageist is my selection here) or (a left field alternative is M Labushange, but IMHO his bowling isn't quite up to it)
J Hazelwood
I wish I could squeeze in AJ Tye - in modern ODI cricket in high scoring conditions "the death" starts early - and another middle order (and top order for that matter) batter - and a reserve wicket keeper. If I *knew* the pitches would be flat, I'd drop Hazelwood for Tye. If I knew the pitches would be green, I'd drop Boyce for another top order batter. If I *knew* Handscombe would get injured I'd select Wade.
But that's my squad. No all-rounder (we don't have any worth selecting IMHO). Only a part time keeper. No Nathan Lyon (our "best" spinner). I've dropped the captain. The squad is light on top order orthodox batting, which I think there is a good chance will be at a premium in this WC if England has a wet spring. But - *if* everyone stays/is fit - we could field a *very* strong 4 pronged pace/seam attack, and win games in the first 20 overs of our bowling innings.
If Handscombe hadn't made runs in India, it'd be M Wade with the (iron) gloves based on Shield and BBL form. I also think Wade's more orthodox footwork and vertical bat would stand him in good stead (or at least better than Handscombe's) in seaming conditions. Handscombe has played more County cricket than Wade, and proved effective, so I'll use that as a basis for selecting him. If he (Wade) wasn't such a bogan I'd probably make an even gutsier call and drop Handscombe for him.
But this is the compromise I've made to allow a team of 4 quality quicks, or two wrist spinners and a bank of middle order hitting to suit the likely conditions.
I *know* this won't be the squad, because one slot will have to go to our clean, white Captain (Finch or Paine) - and it's too much to ask of Pat Cummins at this stage of his career. Another will probably go to Carey. And we will only pick one wrist spinner, in deference to this actually being a strength of Australian cricket *and* legspinning being the hallmark of successful modern ODI sides, even in England.