Is the white ball their child? or just part of the other one's soul? or another flower ent...

You mean that white shadow that Ao Gu stepped on, yes supposedly it's their child from the very first time when Ao Gu forced himself on Tudi. (I think)

I'm confused myself.

I rely on the authors notes to understand the story so they'll probably clarify it for us later (=・ω・=)

It's their child. A carbon copy of Ao Gu with Tudi's eyes

I forgot the spoiler alert. I can't delete this. huhu..

Thanks for clarifying and thank you for your service !!