The 'features' are manually entered in wikipedia and are very chaotic. We therefore don't plan to provide any webservice for them.
On the list are only the 'features' with 10 or more occurences there are thousands of features that occur only once, because of misspellers and other reasons.
The findNearbyWikipedia service does not support paging and the startRow parameter is therefore not implemented (for performance reasons). It is not planned to implement it.