John,
Yes, Ping-O-Matic (or whatever other XML-RPC services you have configured WordPress to ping for new posts) will be pinged when you receive new posts via FeedWordPress. FWP does, however, only send *one* ping per update, no matter how many new posts you receive from that update.
I’m not sure if I understood your second question. The RSS or Atom feed for your site should still be at the normal location (https://xyz.com/blog/feed/ or https://xyz.com/blog/feed/atom or whatever you like). Posts syndicated through FeedWordPress will show up in your RSS feed like any other posts.
Hope this helps.
–Charles Johnson
