Through out the series so far we have seen several ways people can manifest multiple quirks. Such as Todo, which has Fire and Ice powers or Noumus power to steal quirks, allowing for multiple quirks, all though only 1 can be used at the time.
We also know that Nana had her own quirk, and still could receive One for All. Making it a case of literally 2 quirks in 1 body.
But is there a limitation known to how many quirks can be fused into 1 body/person?