He's biologically human i'd say yeah, since he's pretty much a "clone" of another human.
And as for that last question, it'll be answered later, at some point
I haven't read the novel so idk how it was explained there but I think it's cuz little mushroom absorbed An Ze's human DNA and then copied it to make cells from his hyphae (and his whole body) which secreted blood so i guess that makes his blood similar to humans and identical to An Ze. So his blood can be considered biologically human.
Also the blood test to determine whether you have mutated gene is only for identifying plant mutation or animal mutation and little mushroom is neither.
That's also why we have a whole different kingdom fungi to study them cuz they aren't like plants or animals.
So maybe that's why nothing was flagged about his blood since they didn't check for fungal mutation as apparently they don't exist in this plot setting.
An Zhe is a mushroom but since his blood was drawn and nothing suspicious was raised from it, does that mean he's biologically human? But he's not human, we can see it during the insect attack chapter. So how come there's nothing flagged about his blood?
Anyway, if his blood is actually blood, then does that mean he can donate it? If someone else got his blood, will they have mushroom gene in his blood?