I am confused by your request of first generation pokemon only but the inclusion of Teddiursa, Marill which are both second generation pokemon. While Togepi I can understand being included as the anime introduced it well into generation one but it wasn't officially introduced in the games until generation two many will argue it can be considered a generation 1.
So what exactly is your list? Top 10 cutest pokemon in general? Of Gen 1? Of Gen 1 and 2?