I think Bangladesh should always recruit TWO at the same time.
Last time I remember, Tamim and Junaid were recruited at the same time, and atleast ONE of them became regular at every level.
Then It was Shuvagoto and Nasir, and again one of them became regular at every level.
So I think, Bd should recruit Anamul and Mominul at the same time.
This provides competition between two in solidifying their position in the team, and usually one prevails.
Anamul can replace Junaid in test, and replace Ash in Odi and t20
Mominul can replace SN/Nazimuddin in all format