Great followup post!
> I'd like to explore building a simple iOS application to remove any friction from posting updates on the go.
If your site supports Micropub (https://www.w3.org/TR/micropub/), then you can use any number of Micropub apps to post to your site, instead of writing them yourself! In fact, there's already a fantastic start to an iOS app for exactly this purpose, called Indigenous, in beta right now. https://indieweb.org/Indigenous It should be a minimal amount of work to create a Micropub plugin for Drupal, and then you can take advantage of everyone else's work building clients!