I don't think the search of immortality rules out anti-Muggle propaganda. It is simply that you get a lot of followers if you proclaim hatred against a certain group, and Muggles and half-bloods are not very liked to begin with. Voldemort need followers, and it is easy to gain them among those who hate Muggles. Also, Voldemort is not exactly Muggle-friendly, either. However, achieving immortality is his main agenda.

I like your take on the importance of harry's blood.

Seeing as traditionally blood is important in all sorts of magic, it is reasonable to assume that Harry's blood is for Voldemort. Harry gave Voldemort life, and he will be the one to take it. Conviniently, one of the other people used in the ritual was Voldemort's father, who gave Voldemort life in the first place. Interesting to see the Peter was made the third one.