Regarding the HN to sqlite part, I'm writing a "syncer" that continuously updates data from HN to a local sqlite database. Its goal is to enable anyone to have a local copy of the HN dataset to build various projects (like yours) on top of it. I'm about to release it as an open-source project and would love to collaborate to make sure it supports your use case. I couldn't find an email address in your profile, so please reach out if you're interested.