Ekko and Bard synergy?

Watching this game with Bard and my reckless purchase of Ekko straight into a ranked game yesterday (win!) has me thinking. If ekko can dive into a team and W -> bard ult -> would this last roughly long enough to R as ekko and just drop a massive bomb on the enemy team and gain a shield and combo stun them? Second question, what happens if Ekko had a zhonyas/Bard ult at the moment he decides to R? ie 4 seconds after the zhonyas?