Glasc mixologist and imperial decree questions after rule changes

Hi! I have skimmed over the rules changes and also i played a nexus night yesterday! Some questions arised and i was curious.
Now that until the chain is resolved the battlefield is considered owned by the same player (to avoid the rengar flicker to get 1 point free) is glasc mixologist able to play the unit to the battlefield if it's conquered? Like say, i have a mixologist defending, someone moves a dragon there and kills the mixologist, can i play the other unit there? And if so, would the dragon be healed before fighting that unit too?

Also, i had an ahri deck and someone told me that, because of how instances of damage are calculated, if they did repeated bellows with imperial decree, ahri would die, trigger zhonyas, then die again. Is that true? Would it be the same with GA?

Bonus question, does sundisk still trigger itself? I played tcg arena yesterday and a reksai left when i asked so i wanted to be sure :v

Thanks for the help!