also display events in the news feed?

I think Wysija already supports custom post types: https://wysija.uservoice.com/forums/150107-feature-request/suggestions/2729196-support-for-custom-post-types

In our latest version you can add custom post types with Title and Content only. Update your plugins and check it out!

(Kim, November 6, 2012)

However if you want it to display event dates / venues, then you may have to ask Wysija if they provide the ability to do this (e.g. editing some template).