1. Not for the public API
2. If you don't already have the TVmaze ID, you'd search for it;
https://api.tvmaze.com/search/shows?q=girls or https://api.tvmaze.com/singlesearch/shows?q=girls
If you only want future episodes, you could check this response for _links.nextepisode and if it's not present, then there's no future episodes.
Then you'd request https://api.tvmaze.com/shows/1/episodes to get the episode data (you'll have to filter this yourself if you only want future ones).