I don't think it's like that, it's true that currently Barcelona have a lot of strikers there and one of them is Auba and some have potential like Ferran Torres or Adama but on the other hand they also still need goal-hungry strikers like Lewa but like you said when you want to sign players it's clear that there are definitely some who will be sacrificed and there have been some that have entered the radar of other clubs such as Dembele with PSG or some issues regarding Braithwaite with several EPL clubs.
Adama Traore will not be in Barcelona squad for next season because Barcelona is not will to activate the option that is in his loan contract so if Lewadonski leaves for Barcelona it will be a better option but the question is can Barcelona afford to sign Lewadonski following their financial crisis. Aubameyang alone can't be doing all the work all through the season and Ferran Tores is more of a winger. If Lewadonski covers up for Abumeyang it won't be any sort of shame at least it will prove they have good substitute in time of injuries.
Barcelona's main problem is still financial and this is still difficult to control, especially now that a problem has arisen with some players refusing to take a pay cut for the umpteenth time.It will be even more difficult if Lewandowski does come and I am now quite pessimistic about this although I like Lewa to be at Barcelona but this just makes the problem bigger.