I couldn’t finish Ringworld Throne either. My eyes throb at the thought.
Is it necessary to reread/finish this book in order to get/enjoy
Ringworld’s Children.
I really don’t think so. Most of what Throne did was to take us through an adventure with machine people, catch us up to date on the people that Louis and Chmeee met when they killed back the sunflower invasion, let us see the combination take out a huge nest of vampires, and clarify a lot of backstory with protectors. It also introduced us to the spill mountains folk and a specific family of ghouls who have roles in RW Children.
Just bear in mind, as was reflected earlier in the thread, that the protector Louis, et al, were combatting in Throne did start a war with the various human and Kzinti forces now present in the ringworld system. And that he had been a vampire before the virus. You could reread RW Engineers, if that doesn’t frustrate you; it’ll remind you of most of the important/useful stuff. Or you can come back here with any other questions. 