Use as a generic OSM event stream

Hi there! I've built several tools that do stream processing on top of the replications diffs coming from OSM. I have a supybot plugin that spams #osm-bot on OFTC with new users mapping, a Slack bot that spams #new-mappers on the OSM US Slack channel, and some other stuff that I use locally to keep track of things. Each of these tools uses different, one-off style code and I'd love to find something to centralize on. Planet-stream seems like a great possibility...

Would it be possible to run planet-stream without any Overpass server? It's hard to tell, but will planet-stream give me events for *all* OSM changes (changesets, nodes, ways, relations) or just changesets? Is there a built-in way to limit the events received to only one type of OSM "thing"? How would you envision adding support for OSM notes?