Is there any way to bring Lydia back to life with all of her stuff?

on PC you can use console commands but on Xbox or PS3 she's dead for ever on your current character. load a save from before she died if you want her back alive.

I found the resurrect one, but it clears her inventory. I progressed further in the game because I thought that she was fighting someone, and that she would eventually catch up. Is there any way to resurrect her with her inventory?

take all her items out of her inventory. resurrect her and then give her the items back.

Reload the save before the fight where she was killed.

resurrect 1 would bring her back and not a copy of her. But yeah I think it would reset her inventory. Like they said. Loot her of everything and then use that command.