Total Recommendations: 7
both involve incest but BokuImo is a shoujo manga adaptation(in later chapters of the manga-not in the OVA-it is revealed they are not actually siblings) and Yosuga no Sora is a bishoujo eroge adaptations(they are actual brother and sister)...also Yosuga no Sora has fanservice while BokuImo,being a shoujo,has almost none
they are both about love and about couples.While Amagami is about a boy falling in love(in an omnibus style-he falls in love with various girls in different arcs) Hatsukoi Limited is about girls pursuing their love interests(couples are formed with a continuous storyline). They are both good but I like more Amagami
they are both about kids and their teacher..Hanamaru is light-hearted and cute while Mitsudomoe has scary(in a funny way) and older characters and consists of mostly sex-jokes...if you watch Hanamaru and want a cute show then I don't recommend it...
Both are sd/chibi characters short episodes spin-offs.