Well this version definitely looks better to me, I think it’s better to use ActivityStreams as much as possible for good interoperability, maybe have some text to describe data (so location.name should probably be a full representation of the postal address) but avoid extensions (mastodon fields are probably a good example of widely used extensions that are supported only on few softwares).
Also might be a good idea to ping Friendica folks on this, I don’t think they added as:Event support yet but they do have events support.
EDIT: friendica have events in AP as well: ActivityPub at 36C3 – the "!decentral" assembly and fediverse.party