Getting Oliver's tank ready for another little buddy

Hello,

I'm headed home today, roughly 4 days after Oliver died. On my security camera the water is cloudy. Here's what I wrote to my friend about getting it ready for another Betta. I'd appreciate any input thank you!

Tldr can I keep the plants in there? Dwarf grass and dwarf ambulia 😊

I look at it as this; I have a box of ammonia and nitrite water with plants in it that are literally at a free buffet with an open bar. Life continues and Oliver's atoms are inseparable from everything else in there (and the air above the tank). I am going to do a complete water change, substrate vacuum, and rinse the filters in tap water to chlorinate them and kill whatever bacteria, good or bad is in them. Then start over, air dry the filter sponges, throw in some bio-starter, re-cycle the tank and make it ready for another little personality.

The bladder snails might be an issue though. Especially if only some survived the ammonia spike.