I think the titan forms are possessions of Ymir since she molded them from earth. She used it probably because Zeke's titan has a great ability to attack enemies from a great distance, not necessarily means Zeke is dead.
Gabi did kill Eren once, so I think she won't have the chance too do it again. But if it that one in a million chance happens, I'll give you a lighter and a ton of gasoline.
You missed a crucial point: Eren waited until Willy Tybur, an Eldian teaming up with the rest of the world declared war on Paradis. Eren has to act this way to prevent his people from getting killed. That alone justified his act enough. Your r*per is not justified because the victim doesn't do...
I wonder if Eren has enough strength to keep it up until he destroyed the world. Maybe he will die of exhaustion, then the rest of the world that are still in tact would truly fear Paradis and leave them alone for good this time?
So only Falco can pull out the true potential of the Jaw huh? Other Titans can also be bigger and stronger, depending on the nature of the Shifter, or because Falco drank some of Zeke's spinal fluid that his Titan got a little "beasty"?
This feels really rushed but I think Isayama has this problem a few times: he struggled to meet the monthly chapter's length. Otherwise it's great, the only logical sequence of action in my opinion. Also one person's POV is still missing that I would like to know: Historia.