The fastest query is the internal ID lookup, which is not surprising. The ID value itself (avoid it as an external identifier) is tightly coupled to the stored data structure. It is roughly equivalent to telling Cypher where the node is in the node store file. (*)
For the next two fastest ones, I might be totally mistaken, but I think they are faster because you match a path only, although I'm not sure how exactly this influences the query behaviour. The small delta between the two can be explained by the fact than one query is using the schema index under the hood, while the other is not (as the label isn't specified in the second case).
For the last 3 ones, it might be that the start point location lookup time is very irrelevant compared to the depth of your relationships PARENT_OF. You may end up traversing long paths, I'm not sure.
(*) Still I don't understand how just a lookup by ID of the start node would explain such a difference with the similar 2 slowest queries (they also don't match by path...)