Here goes!
1) You would say 'what kind of movies do you like?'. If you were talking about other people (and more than one person) you would say 'what kind of movies do they like?' If you were talking a bout a SPECIFIC movie, then you would ask 'did you like the movie?'
2) That kind of person, or those kind of people. You can see the difference here, when you are referring to a single person, or several people.
3) 'I like a special kind of series' There is no word in English 'serie'. Interestingly, there is an Italian word 'serie' as in the football league, 'Serie A'
I hope this helps, but just let me know if you need any more help.
Geoff