It's not clear exactly how spore druid will be implemented (it's unlikely to be exactly the same as PnP, since in PnP it's broke), but they will probably get something similar. Probably capped on one spore zombie minion at a time.
In PnP spore zombies have 1 Hp which would make them useless in BG3 as they would die walking. I would recommend a few changes to them, but we will need to see how larian homebrews them. Albeit suggestions ...
1) Gaseous Indignation: AKA ghoul fever homebrew: Enemies hit by spore zombie have nauseated debuff and -1AC and -1Constituion
2) zombies health = CR of enemy /10+ caster level +wisdom modifier. Eg: cr 20 enemy [lvl 8 druid, 18 wisdom] with 20 health zombie would have 2+ 8+ 4= 14 Health points.
3) immunity to poison, necrotic, and disease damage