TAM, now Brazil's largest airline, is due to start to LHR from 28th October, with A330s. Whether that's in addition to Varig or on its own depends on, well, whether RG lasts that long. Certainly, TAM will give BA some competition, as its service product is said to be better than RG's, which has declined over the past few years (very little IFE on MD11s).
As for IB, I don't think that would be a very welcome; I've heard some very unfavourable comments about its inflight service to South America.