Help with ascending

At this point most of my good champions are rank 4 champions, and Ezio and Kael are at 5 star but not maxed out yet.

First question: Is there a commonly known tool to understand who in your collection should be leveled up first and so on? Or is it like just level up who you like but focus on their stats so they’re not dead weight? I’m sure not all champions are universally good if leveled up properly. At some point I’m sure certain champions will not have enough survivability in order to remain useful. But I’m still new so I’m prepared to be wrong.

Second question: Is ascending just as easy as maxing out low level duplicate champions up to the rank you need and then feed them to the champion your wanting to ascend? Or is there a better method or process that I’m missing?