I posted this in the modx support forum as well - please forgive the cross post.
Issues/Gotchas:
there appears to be a caching issue, I got things up and running, added a couple of events but they did not appear in the chunk output. I cleared the cache VIA the manager interface but no dice. not until I went into the site VIA shell & deleted the contents of /core/cache did the new events start showing up.
http vs. https, https protocol does not appear to work. Taking a quick look at the code, honestly not understanding all of it, the RSS parsing is done by a modx core module? - is this what is not respecting the https protocol? [luckily google calendars will use either]
I posted this in the modx support forum as well - please forgive the cross post.
Issues/Gotchas: