That would be interesting. But Ryukishi07 tries to keep Umineko separate from Higurashi.
In the Umineko VN world, Higurashi was just a regular book. In Umineko anime world, Higurashi was an anime that Maria was watching.
The only 2 characters that really connect the stories are the witches Bernkastel and Lambdadelta. They said that they used to play some "game" and it might have been the battle between Rika and Takano. Bernkastel is also similar to Frederica Bernkastel, the witch that Rika herself mentioned in Higurashi Rei.
There is also Featherinne Augustus Aurora who kind of looks like Hanyuu. She has a crescent floating around her head that resembles horns, and "Augustus Aurora" can be shortened to "Au Au" (Hanyuu's catchphrase), but it's all probably just a parody.