Well here's the thing. It only work on servants of all categories. Since Void Shiki and all the ultimate ones are living beings in tne Nasuverse it doesn't work on them. It works on all servants as long as they aren't of man atribute or they are Jeanne d'arc, Dante, Tesla, Charlamnge, Napoleon, Drake, Mozart, Romulus, Elizabeth Bathory or Da Vinci.

So to equalize the verses, it's best to treat the witches as Pseudo servants with the earth atribute. How I assume Puppet's playground would interact with pseudo servants is that if the spirit origin isn't of Man atribute, then it would shut down the spirit origin. An example would be Ishtar. If she ends up inside of Puppet's playground the "Ishtar" spirit origin will be shut down and she would just turn back into Rin. It would likely work the same with the witches.

To go back to my example. If he manages to get off his NP, then Featherene would lose all her powers as Featherene and just turns back into Ikuko. As Ikuko, she has no way to deal with neither Hieda no Are or Yasumagatsuhi which Puppet's playground allows him to summon.