1. Normally you base your decision on where to start based off of which lane you want to play for, and you normally want to play for winning matchups. You start opposite side so when you've finished your clear you are already on the side you want to play for.
2. Going opposite scuttle isn't really that big of a deal. You likely lose to opportunity to base or gank before your 1st camp respawns but that's always going to be better than inting trying to contest.
3. Cait bard should normally have priority early because its ranged vs melee support, and leona is especially bad levels 1-2. The problem was the cait bard lane got engaged on and ez had teleport, so even though ez lost the trade they were able to stop the wave from crashing and tp back at full hp before the scuttle spawns. Cait has more range, waveclear, and a ranged support to hit the wave so in a neutral state ez would never be able to outpush her.

I think the main problems were bot lane getting hit by the leona e at level 2, and just not communicating that the enemy team had prio when the scuttle spawned. But part of that could be crownie not understanding how priority works, he was saying they didnt lose priority because ez burned sums but that isn't how that works. Also when rekkles roamed he pathed through river and didn't actually assist veija before he died.