She talked about this a few times when she presented the program 'Hoje em Dia'. Even in southern Brazil it is almost impossible for someone not to have Iberian descent. The Germans who came to Brazil mixed with Iberians and natives.
Even Brazilians of German and Polish descent are at least 40% Iberian. Most of the time the descent from other parts of Europe is no more than 30%. There is research on this - I have already published about autosomal genetics. Most of the descendants of Brazilian whites are Iberian, followed by the Italian and only later Germanic. Brazilians with Germanic surnames are not usually more Germanic than Iberian or Italian.
Did she? I don't doubt, but I'd like to see it, since I thought she was German in ancestry, given the area where she comes from and the data available on internet. If she is also Iberian, then she is. No problem. But that would be news for me.
As for the study you posted, hmm, again: it includes the city of Pelotas only, not South Brazil as a whole, neither the state of Rio Grande do Sul entirely. And no, it's not almost impossible for someone in S. Brazil not to have Iberian descent (no offense, but this statement is not correct). This is not good nor bad. It is what it is. I'm from RS, btw, and I don't. I also know one or two things about the place where I was born.
I naturally knew many, many people in there who don't have Iberian descent either. It depends on the area, of course. There're virtually whole cities in which people have almost only N. Italian ancestry, German, a mix of these two... And where people actually still speak the related dialects. Indeed, I dated a girl from another city who had only Germans in her tree (to provide one example), not to mention full N. Italians dates (not my choice; they were just frequent). The German one is 2nd great-granddaughter of Germans, or something; amazingly, her family still spoke Hunsrückisch (also Portuguese, obviously), after so many generations.
Now, am I saying that most of "gaúchos" has no Iberian ancestry? No, I'm not. Not sure about SC, but most of gaúchos must have also Iberian ancestry, yes. It's a big state. What I'm saying is that many don't, and the frequency will depend on the area we're talking about: the highest ones are in big part of Serra Gaúcha, certain cities of Vale dos Sinos, Vale do Taquari, Vale do Rio Pardo (Ana Hickman's area), parts of Planalto Médio or north of the state as a whole... In SC, all state with exception of Campos de Cima and the coast.
So, what I'm saying is that it's not
almost impossible to find them. Far from that. Perhaps it's true for Southeast region? Possibly with exception of parts of ES...
Anyway, these "Europeans" areas are actually the source of that "Southern" stereotype of light people. A stereotype that doesn't make sense for big part of the South, obviously.