I'm a little concerned with Dupavillon. Out of the all the young bowlers around he is the only seamer that their franchise would do everything they can to get him playing in the XI. But that's two seasons missed now with minimal bowling. This off-season is massive for him which will lead into a key season for the Dolphins if he can stay fit. At 24/25 you would hope that the injuries start to end. It's bizarre as he wasn't injury prone when he was younger. Can only remember when he broke records at Khaya Majola Week he had to miss the SA Schools game with a slight side strain after KZN Inland probably over bowled him. But if the Dolphins can get him consistently on the park he is the most exciting of the rest there is no doubt.
Dale Steyn 35
Vernon Philander 33
Kagiso Rabada 23
Lungi Ngidi 22
Duanne Olivier 26
I would go with your list Stephen as I what I have seen and the expectations around them they would have the highest ceiling. I do agree with PEWS that B.Hendricks like Olivier potentially be stop-gaps. I think the SA 'A' attack vs Australia in Benoni was spot on.
It isn't the be all and end all but it's good to know who can win games at a lower level. Consistency also counts though as you may get 3 or 4 4-fors but it's just an interesting perspective (someone like Morris).
But in recent years the youngsters who have come in to franchise cricket and taken 5-fors is Dupavillon, Rabada, Nortje, Ngidi , Mulder , Cohen
The below shows why Olivier is where he is now.
5 wicket hauls by season
2017/18
Cobras : Cohen (1)
Warriors : Harmer (3)
Dolphins : Maharaj (2), Engelbrecht (1), Mungroo (1)
Knights : de Lange (1), van Schalkwyk (1), McLaren (1)
Lions : B.Hendricks (1), Phangiso (1), Fortuin (1), Pongolo (1)
Titans : Ngidi (1), Siboto (1), Shamsi (1)
2016/17
Cobras : Paterson (1), Kleinveldt (1), Piedt (1)
Warriors : Nortje (1)
Dolphins : Maharaj (3), Frylinck (2), Muthusamy (1), Subrayen (1)
Knights : Olivier (5), de Lange (2), van Schalkwyk (1), Peterson (1)
Lions : Viljoen (2), Pretorius (2), B.Hendricks (1), Mulder (1)
Titans : von Berg (3), Ngidi (1), Siboto (1), Wiese (1)
2015/16
Cobras : Parnell (3), Piedt (2), Peterson (1), Kleinveldt (1)
Warriors : Harmer (1), Nortje (1), Magala (1), Walters (1)
Dolphins : Maharaj (3), Alexander (2), Dupavillon (1), Savage (1), Tahir (1)
Knights : Olivier (3), Siboto (2), van Schalkwyk (1), du Preez (1)
Lions : Viljoen (4), Pretorius (1), Matshikwe (1)
Titans : Shamsi (5), de Lange (1), Richards (1), Mbhalati (1)
2014/15
Cobras : Paterson (2), Muller (1), Linde (1), Shezi (1)
Warriors : Birch (1)
Dolphins : Abbott (1), Dupavillon (1) , Maharaj (1), Pillans (1), Smit (1)
Knights : Du Preez (1), Dry (1), Coetsee (1)
Lions : Viljoen (4), Rabada (2), Pretorius (1)
Titans : Richards (3), de Lange (1), Mbhalati (1), Wiese (1)
2013/14
Cobras : Piedt (4), B.Hendricks (1), Muller (1), Paterson (1), Kleinveldt (1)
Warriors : Harmer (3) , Parnell (1), Birch (1)
Dolphins : Abbott (3), Dupavillon (1), Smit (1), Maharaj (1), Shamsi (1), Alexander (1)
Knights : Friend (1), Dry (1), Coetsee (1), vd Wath (1)
Lions : Viljoen (2), Tsotsobe (1)
Titans : Wiese (2), von Berg (1)