This has essentially never happened in recent memory, Halland joined after Aguero was out, Kane was signed after Ldwa was out, Mbappe joined after a year of Bellingham leaving.
I don't know if its happened or not, but in the examples you gave Aguero left ManC when he was 33, he was younger than Lewa now.
Ours is a unique scenario where our No9 will be 38 when his contract ends. None of the clubs had to account for that, and from your examples, they replaced theirs way before the striker even reached 35. Lewa is already 36.
I think we will have the funds to manage both.
Regarding other signings, yes we need a fullback, GK too but I am hoping Wojak will continue. Dont think we will need to pay for a CB, Tah should be available for free.
For me, a Striker is a priority for us than a LW. Raph is doing pretty well and I don't think at this moment no player can replace him. We should spend the money for a winger on a striker and our jobs done.
If we are not able to sign a Striker or even a backup who can take the reins from Lewa, I fully expect us to have a very poor March/April of 2026. Unless Pau Victor or Fati became what we all want them to be.
I like Marmoush though, as you said he plays LW too, so he can be utilised well.