You could always just use the rules for diagonals on page 252 of the DMG

Jesus saves! Everyone else takes full damage

And if you take 3 levels of armorer you can have your armor change to fit your new form to have a good AC and shoot lightning as you slither around as a robosnake

Just take reborn as your race and live your dreams

I have tried doing XP triggers before and I found it a little difficult to keep it fair between characters. If I were to do it again I would award the whole party XP when an individual fulfills a trigger.