That is a very broad question - there are many things to consider when you decide who to sign - the obvious answer would be to sign the best two ones, but how to determine who those two are?
Potential ability and current ability
In terms of potential Destro is the only one of the above that has a fixed potential ability - at 168 in potential ability he is certain to be a quite good but not great worldclass striker.
Fierro, Ademilson, Adam Campbell, Benzia and Yesil Samed are all -9 players - that means that their potential ability can be anything between 150 and 180 - I don't know who Victor Andrade is - I can't find him in the game. So you have at least 5 players who could have a higher potential ability that Destro and hence, you need to scout them in the game to see who gets the highest potential rating.
Looking at current ability, the players rank as follows (from the offset of the game):
Destro: 135
Ademílson: 126
Yassine Benzia: 114
Carlos Fierro: 105
Samed Yesil: 97
Adam Campbell: 90
You can view this two ways - the higher the current ability, the less time until the player reaches full strength, or the lower the current ability the more time to train and develop the player to reach their full strength. I.e. the question you need to ask yourself is how long am I going to play and do I need a player who can step into my back up team right away or are you looking at someone who can stay a few years with the reserves until he gets a taste of first team action.
Purchase price
Another important aspect is of course how much they are likely to cost
Adam Campbell is the cheapest at around £575k - £750k, Ademílson has a minimum fee release clause of £5.313.600 whereas Destro is even more pricy.
Important attributes
It is a bit of a funny thing to decide based upon current attributes because we are talking about talents and thus they will develop like crazy. But if you plan to play some of them as rotation from the start then it becomes more important. Looking at the role of poacher the some of the important technical attributes are first touch, finishing and dribbling. Important mental attributes are anticipation, composure and off the ball wheras it is also important for a poacher to have decent acceleration and pace.
I have listed the players' attributes in first touch, finishing, off the ball and acceleration below:
Destro: 13, 15, 14, 14 (56)
Ademílson: 13, 15, 15, 14 (57)
Yassine Benzia: 15, 13, 13, 13 (54)
Carlos Fierro: 9, 11, 14, 12 (46)
Samed Yesil: 11, 14, 15, 12 (52)
Adam Campbell: 10, 10, 10, 17 (47)
Quite surprising we can see that despite the large difference in current ability, Destro is not leading in terms of attributes. Both Destro, Ademílson, Benzia and Yesil are all decent poachers already. Fierro and Campbell are one or two levels below the other four.
Age (and home-grown)
The final thing I would like to shine on is the age of the player - and more importantly whether they can become home-grown at the club which is critical later in the game when to play for example in Europe. Clearly all players who share the same nationality as the team they are playing for are home-grown, so if you are playing with for example Inter Milan, then Destro is extra attractive due to his Italian passport.
But there is another way for players to become home-grown. They become home-grown if they have played at the club and/or nation for two years before they turn 21. I.e. if you can get a player to your club when they maximum 18 years old then they will become home grown (unless you loan them out to a club playing in another country).
Of the players you mention Campbell (17), Benzia (17), Yesil (18), Admílson (18) are all 18 or younger whereas Destro is 21 and can only be home-grown if you are playing with an Italian club.
Conclusion:
Based upon the above, I would prefer Ademílson, Benzia or Yesil. This is mainly due to their current attributes in the role of a poacher as well as their age and thus their ability to become home-grown for my club (I am playing with Chelsea).
To make the final decision, I would scout all three players in the game - In my game Ademílson and Benzia gets 4½ star in potential ability whereas Yessil gets 4 stars in potential ability. In terms of price, Ademílson costs only £5½ mio. due to his minimum fee release clause whereas Liverpool want £8½ mio. for Yessil and Lyon want £9½ mio. for Benzia.
Based on the scout rating and the price, I would end up choosing Ademílson as my first pick and given the relatively small difference in purchase price between Benzia and Yessil, I would pay the extra million £ and get Benzia as my second choice.
I hope this helped
