Your original statement implied that the ST/PH team are the main people responsible for SS, which still is as wrong as half an hour ago. They are a small part of a much bigger team.
I don't care if they put their fingers into another game, but I absolutely don't want to see them doing something on their own again. (And even if there aren't multiple teams formally, the fact remains that ST/PH were developed by largely the same few people)
Also, whether or not Grezzo will develop original Zelda games still remains to be seen. So far Nintendo has only used them as code-monkeys. Assuming that they are going to develop the next handheld Zeldas from now on is a case of jumping to conclusions at this point.
Again, jumping to conlusions. There are other reasons why Nintendo potentially wouldn't want to develop two handheld Zelda games at the same time -- brand saturation for one.
It might very well be the case that Grezzo will develop the next original handheld Zelda game, but assuming this because they've done mere ports (on top of that, one port with no additional content by Grezzo at all, and one with cool but rather subpar additional content) strikes me as far-fetched at this point.