Standing right now, that 2019 WC is probably the most open WC since 1975 (when ODI game was baby), because of absence of any outstanding team. Aussies & SAF are probably at their weakest in last 25 years (AUS since 1985), India isn't that exciting either, while Poms will need to do lot more on field to match their off-field hype. Kiwis, SRL, WI are in serious decline; therefore I do believe that at least 7 teams including BD has a chance to make the SF, may be all 9 in this format - after that, it's about 2 outstanding day outs by any of the top 5 teams; which means any of AUS, ENG, IND, PAK, SAF can win it.
To have a realistic shot at the WC, which will be played in June, 11 matches in 5 weeks or so, I see only 8, may be 9 players surviving from this team. Or other way, if 5/6 new faces are not integrated/found - don't see PAK winning it. I'll look for a combination of 16 players, for a WC in UK, in June. Not necessarily, every new face has to be in starting XI, but they must be good enough to force existing starters improve their out put, or lose the spot. Here is my combination -
1. 3 Openers : Fakhar & best case scenario is Sharjeel & one new face. But, one of Azhar or Shehzad can be there, but no way both. Ideally, at least one of the 3 has to be lefti. Best case is probably - Fakhar, Sharjeel, Ahmed - not sure how good is Zeeshan Malik, but I would like to believe that in 2 years, he'll be better than both Ahmed or Azhar; Farhan is an outside shot, but long way to go for him.
2. 4/3 Middle orders : Babar, Open spot, Open spot. I would like to see at least 1 lefti in this mix - Haris, subject to fitness & Amin may be enough, but PAK should find one more young middle order from junior ranks. At worst, one of MoHa or Malik can be picked for the squad, but no way both.
3. 3/4 All-rounders : At most, PAK should carry 3 spinners; all of them are actually all-rounders, because of Shadab's potential - Shadab & Imad. I don't consider MoHa or Malik as all-rounder any more. Rest 2 has to be pace bowling all-rounders - may be one of Fahim or Yamin should make it, but not both - so one spot is still open. If he can improve his overall game, Aga Salman Ali has a decent shout, so is Usama Mir, but 3 spinners are difficult to accommodate in UK - last time Iqbal Qasim & Misbah did that in 2013, rest is as they say - history.
4. 2 WKs : Sarfraz is obvious pick. For the other one, it has to be a batsman, who can make the team as batsman, but can keep. PAK can't go to WC of 9 confirmed matches in 29 days, with one WK who happens to be Captain & next best man in squad to keep is probably Babar

. Unpopular choice, but Umar has to be kept in consideration - for that, he has to shape himself, or PAK goes for a new face, even like the kid Ruhail Nazir. Don't see any role for Rizwan, because at his best, as back-up WK, who can make the squad as batsman - still he isn't good enough to what is Umar Akmal right now. In AUS, Rizwan got 5 bites at the cherry - and he should have been demoted to No. 10 from 6, by the 5th match, on his batting merit.
5. Spin Bowlers : I won't take any specialist spinner - one reason being there none outstanding one, neither the condition suits to play a specialist spinner. At best, both Imad & Shadab should play & that's enough - at worst, may be MoHa/Malik can be picked in XI for few overs of spin as 3rd spinner. BUT, PAK must keep Usama & Yasir (Or the other leggi Irfan) on toes, because if Shadab gets injured, one Leggi is a must for any ODI these days, for the batting quality these days against even non turning spin.
6. 4 Pacers : At present, I see only 2 bowlers ready - Amir & Hasan. May be, if he improves his bowling to the level of 2012-13, JK can be the 3rd one; otherwise not, because by 2019, he'll be 29+, officially, with a dodgy knee and action; too risky to invest without alternatives in mind. PAK must find couple of new faces for those 2 spots - I am not sure who are those but these Raees, Hamza, Irfan, Sohail, Wahab, Shinwari ..... won't work. PAK's game tactics should be 3 flat out pacers to attack & 10 overs of attacking leg spin - last 10 overs can be shared by all-rounders. Those 2 new pacers are to use the new ball, partnering Amir as Hasan is doing great as 1st change, I won't move him to take the new ball.
Don't know how good he is, but may be SS Afridi can be one of the 2 new faces (that makes the job tougher for JK - won't pick 3 lef-armers, unless the 3rd one is far better than 2nd best right armer). Both, have to be a good new ball bowler to partner Amir and preferably right armer. Apart from SS Afridi, other one is a toss between JK, Ehtesham, Irfan (shorter one at 6'4"), or may be entirely new face, I don't know - BUT, existing resources are not enough.
If Sharjeel is available (which I think, he'll be), I would open with Babar & put Fakhar at 3 - that gives a good left-right combination, and Fakhar is better spin player while Babar is far better again pace, and his game is built on touch, should find gaps better in PP. SK's hitting ability should allow Babar to play natural game & it'll trouble bowling unit - for SK's ability to smash anything short while Babar is a fantastic driver on the rise; adjusting to sweet length & line will be a challenge for new ball pair. Otherwise, teams best batsman should bat at 3.
So the 16 men squad stands for me -
1. SK (Or Fakhar opens with the back-up opener & Babar goes to 3)
2. Babar (Position depending on SK's availability)
3. Fakhar (Bat's at 3 only if SK is available, otherwise swaps with Babar)
4. *Sarfraz +
5. Haris
6. Umar (Must improve over all game & his defamed image, otherwise MoHa/Malik comes and this spot becomes open for a new face that's good with bat & can keep)
7. Imad
8. Shadab
9. Amir
10. Hasan
11. Open spot (SS Afridi/Ehtesham/JK?)
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12. Amin (Or Open spot - BUT no way both Mian/MoHa though this back door)
13. Open spot (Ahmed/Azhar/Zeeshan/Farhan ?)
14. Open spot (Ahmed/Azhar/Zeeshan/Farhan ? or Yamin/Fahim/Ammad/New kid ?)
15. Open spot (JK/Ehtesham/SS Afridi/Irfan?)
16. Open spot (MoHa/Malik/Aga Salman Ali/Mir ?)
That's at least 5, up to 7 open spots to cover in 20 months - won't be easy, but indeed possible. Availability of talent was never an issue even in those 9th ranked days, but I don't see enough A team matches for PAK to test options within this one year period, because by Jan 2019, 19-20 players has to be locked, no more experiment. One good suggestion could be to play 5 X 3 = 15 ODIs against ZIM, IRL & AFG; where about 8/9 new faces are tried. Result doesn't matter here, because PAK A should win 15-0, but PAK 1st team got knocked out by IRL 10 years back - those are one off, one shouldn't bother for such odd day, as long as the bigger purpose is served. Problem is, if such series indeed take place, PAK might end up filling the squad with Amir, Hasan, Imad, Azhar, Shehzad, Malik, MoHa ..... who knows, even Gul, Kamran, Irfan, Wahab, Tannu, Annu .....