If you count the announcer for the versus mode and the head skin people can wear of Wesker as a return sure, but I don't unless he is a C-Virus clone or something.
More than anything, I mean the plot role of the company leader who watched 3A7. Through Jackson, we got a portrait of Wesker, including his status as a legend and how well he knows the Spanish village and the cult incident, as if he was there.
And only then I appeal to the negotiations, where Douglas's Wesker-like voice says that the rumors about his demise were slightly exaggerated.
This is a Wesker character, without a doubt. Technically, it could be Wesker himself, his clone or a copy of consciousness, whatever, but we understand that his figure was brought back to return to the old Umbrella thread as well.
The NE-a being linked to G added a layer I agree, but in the originals Umbrella had no idea what the Plaga even were.
I'm sure the company still doesn't know either. As Sakata said, Umbrella discovered the parasite in the wild, and it became the basis for the artificially created Nemesis.
This is the same lore, the company just found a reference to work with. And it could have found the parasite in Africa or wherever, because it's an ancient life form. It's not necessarily something we'll get a callback about in the new game, because it's part of the Biohazard RE:3 setting.
That's why Wesker sought after them to begin with since it was a new discovery.
The whole reason for Saddler's success was due to the fact that the parasites hidden by the Salazar family were not fossils, but actually mummified, so they were able to secrete spores. No one knew about it and did not expect it at all. Therefore, the cult was able to resume the parasite population and genetically modify them eventually.
Meanwhile, Umbrella was creating everything from scratch, so their artificial parasites were killing the human hosts.
I just can't see how the series can seem extremely consistent when the recent remakes change around events, likeness' of characters, etc.
Remakes are basically just a new round of retellings. They take liberties because unreliability is part of the design of such retrospectives.
If we recall the events of Last Escape from The Umbrella Chronicles, the Pursuer doesn't even infect Jill there, although this scenario is related to Sergei Vladimir and the narrative of the game. And after that, Biohazard 5 acknowledges that Jill was actually infected in RC.
But if you take games like Biohazard 7 and Biohazard Village, I strongly doubt that you can blame them for the inconsistency, because they perfectly fit the time line. They may look different because of a different engine, "feel" different, whatever, but they are completely consistent in terms of writing. Because they are not designed as unreliable narratives, respectively.
Meanwhile, The Umbrella Chronicles planned a retelling of Biohazard 4, but it was cut.