For clone au what happens if one of the obitos dies
Honestly this one really depends on when and what Og!Bito is doing. Whether he takes the chance to go home or he continues the plan.
It's a prime opportunity. He can infiltrate if he wants and no one will know the difference if he plays it right. Not Kakashi, not Minato, not Kushina. In fact, pre-kyuubi attack (even post actually) I'd say Og!bito wishes that clone!bito would die. He is so deeply jealous it's unhealthy.
Only his death should mark what's his so deeply. How dare this clone scar over the wound he left on Kakashi. How dare he fit into the hole he left behind and how dare he do it seamlessly.
Seething indignation. And so when clone!Obito dies, he's happy. Imagine watching from the outside in as an imposter skulked about with your friends and family wearing your skin and they didn't know it wasn't really you? And you can't say anything. You can't tell them that's not you because you've given up being ‘you’ for the sake of a greater purpose.
The world is fake and if they want to play nice with a meat puppet then what's that got to do with you? (But it's got everything to do with you.) You're no longer yourself, rather, someone else’ living will.
Anyway. I think if Og!Obito died stuff on the world domination side of things falls apart. Zetsu would have to go for the ‘back up’. He might have to break Obito in again but oh well. He knows it can be done. They've planned and executed it before. This Obito just has a different 'Rin'. New pressure point, same song and dance.
Would it work? I want to leave that up to individual interpretation, I think it's a lot more interesting that way.