I think that by choosing Ana Tiemi and Dani Lins, Brazil is investing in its future. Physical attributes as well as setting skills should not be an issue as these are all moot at this point. The mistakes they might potentially commit at this point and in the next one or two years should not be taken against them or should not be used to condemn them as the said mistakes facilitate learning and provides experience - international experience they badly need for the coming Olympics. Should these setters develop into their full potential or even 3/4 of it, then I guess Brazil can have a stable setting for years to come.
Maybe, Brazil could also give more playing time for players such as Natalia and Joycinha as they would be the veterans that would lead the future Brazilian NTs.