User blog comment:The Dragon Demands/Season 5 trailer officially released/@comment-1600847-20150130164618

Apparently Lady Stoneheart isn't there either, her actress isn't in Season 5.

As for Aegon, I'm sure they're just waiting before revealing him. Plenty of season 5 actors are listed as "Role: To Be Announced". If they said "Role: Aegon Targaryen/Young Griff", it'd be a HUGE spoiler and ruin the surprise.