1 - This website's "Today' top headlines includes an IAAF release, about medaling in multiple events at World Youth Championships, that should have included mention of that meet's Regulation 403.4.3.
"The maximum number of events that an athlete can compete in is two individual events plus the Relay. If the two individual events are Track Events, only one of these two individual races may be longer than 200m."
So a fine 800m / 1500m runner can compete in only one of those events -- and in no other race longer than 200m.
2 - World Youth Championships have previously been labeled a "kiddies meet" by some discussants. That "kiddies" label is inappropriate considering past participants such as those listed at the IAAF website:
1991- Yelena Isinbaeva in pole vault
2001 - Valerie Adams in shot put -- and sprinter Veronica Campbell Brown
2003 - Usain Bolt in sprints
2005 - Dani Samuels in Discus
2007 - David Storl in Shot Put
2009 - Kirani James in 200 and 400