As a general principle, you can't be fully confident about the reading of a Japanese personal name until you ask themselves or their family (like in English, too, where we have "hue-ston" Houstons and "house-ton" Houstons, for example).
Talking about possibilities, 小此木 may be read as おこのぎ, おこのき, おこぎ, おこき, おひき, おびき, ここき, ここのぎ, こごれき, ここぎ, このき, こひき, こびき, こひぎ, こしき, こしぎ according the link, but I've personally only heard of
おこのぎ or ここのぎ.
For your second person, it seems that 森 is his surname and 廣 is the given name. The one letter 廣 as a given name is most likely to be pronounced as ひろし, but I can't deny the possibility of こう.
小此之本 in your Yahoo! Ask link is probably a mistype or misunderstanding by the poster for 小此之木.