Yep, the outer ring is non-relightable and rely on the launch ring to light them. That said, part of the benefit of having so many engines is that you can tolerate a couple of failures. Similarly to how F9 is able to make orbit with an engine out. Still, agreed that they'll probably opt for one more water landing test first. Especially since the current license allows for multiple launches of this profile if the booster trajectory is fine.

I think the number is 3 so losing one immediately isn't great. They're much more reliable though than that first launch where so many failed.

oh interesting, i did not know that. Just before ignition there was a bottom up view of what looked like gaseous o2 pouring out, was that the priming? They do that to get the pumps spinning to get pressure to the pre-burners so they can ignite and then get more power to turbo pumps to bring everything up to full power correct?

Could have been cool down, but also could have been the fire suppression system which uses (as I recall) both water and nitrogen to avoid combustible gas accumulation below the launch platform. That activates not too long before ignition, before the deluge.