@CM30 These all feel like good predictions, except the last one. I don’t think the Toymaker will ever return.
First, because the Doctor sentenced him to stop existing. He literally doesn’t exist anymore. I know nothing is truly dead in fiction, and doubly so on Doctor Who, but still. It feels very final.
Second, because I don’t think it would be easy to keep getting Neil Patrick Harris back for the role, and I also happen to think his portrayal was so good as to be “definitive”. He is an actual puppeteer, he can do card sleight of hand, he can juggle, he can sing and dance, he IS the Toymaker. I think RTD knows another actor would feel underwhelming in the role.