So I decided to look that up and as far as I can tell they don't generate tags or anything from titles (tags are user defined, but they have an AI working on that) but when you search for a term it will determine the results based on similarity to search and the currently "hottest" videos.
So basically, yes, putting more tags in a title would help it be seen. Although the help section for video metedata does state under "How to Write a Good Title:" "Don't make the title too long, as users will lose interest."
Actually, this might be technically possible. If their mother was a surrogate for her ex and his new wife then got pregnant with her and her new husband's child at the same time they might be considered step twins. So, very unlikely, but still possible I suppose.
So basically, yes, putting more tags in a title would help it be seen. Although the help section for video metedata does state under "How to Write a Good Title:" "Don't make the title too long, as users will lose interest."