@Irelephant at least .osm files can be loaded in #JOSM, but if your extract is big enough (say, a city or bigger), it might clog it, since it will try to render _everything_. It's mostly aimed at loading changesets, not whole areas.
After that, it seems like you can convert the pbf into a SQLite/Spatialite DB and load it in #QGis, but you're already transforming the data.
EDIT: yay! Federation works! (Answered from Mastodon :)