An alarming number of housemate descriptions were true last year, perhaps 8 or more.
If one person goes every week for the first 10 of the 11 weeks, we'll have only three left in the last week, and they know that's a bad idea. Therefore, they are either missing a week or they must be putting in at least one extra person in at some stage.
The only way they can miss a week and not lose revenue is do a fake eviction thing like last year. Given Fight Night, they might not be able to justify doing such a thing.
So any rumours of the identity of A N Other housemate can't be completely dismissed. But surely by now they've realised that latecomers just get flushed out as soon as possible. The net gain is normally very little.