Reworked Urgot ult interactions

Hey, Since Urgot's rework came out, I really want more info about how the ult Works. I've read some stuff, but there are some interactions that aren't clear to me: What happens if Urgot ults an Alistar/Olaf and then Alistar/Olaf ults? What happens if Urgot kills someone with GA, Zilean ult or any revival passive (Aatrox, Anivia and Zac)? If Braum blocks the projectile and he's low, can Urgot kill him or the projectile will be destroyed? Can Urgot kill Tryndamere or Kindred while his/their ult is up? How does the health threshold works on Kled?

Thanks :)