In Ca, if two owners are listed on a 3day notice , and one owner dies, can still Evict tenant if didn't remove deceased name?

Yes you can still evict. No it should not cause a setback. "A dead man cant be in court" That part does not matter. Both owners are not legally required to go to court anyway. Perfectly legal for only 1 to go.

"I read that the 3 day notice must be up to date and perfected before going to trial." Yes & no. What is important is that the notice was accurate as of the date it was served.

Yes to the original question, no to the updates. The rights of the deceased transfer in full to the survivor and it has nothing to do with the tenant. And if both owners die at the same time, or the surviving owner dies, before the eviction gets to court, their estates have the legal right to pursue the eviction. If you owe me money and I die, you don't get a free pass. You pay my estate or my estate sues you.

Yes.

Yes

yes

The agreement can't legally be changed easily to remove a person that's passed or moved out unless all tenants pass or move out. That's why their name is probably still on it. Because the agreement hasn't yet expired or the owner is acting on a previous agreement and going through the eviction process.

Good luck depending on that.

The "alive" owner is perfectly capable of evicting the tenant without his deceased partner. In fact, the dead guy should still be shown as an owner because his estate would now own half the business. Until they determine how to distribute that half, the alive owner would have to conduct the business on his own. He should not remove the deceased's name.

Either of the two landlord can represent the other in court.

Yes.

Update. That will no delay anything.