Now that he looked back, it was a huge risk on his part to bring them on the main floor at that time. If by any chance they had some malevolence hidden, his dungeon core would have been compromised.
Although he had the white palace to protect his dungeon core it was still a considerable risk. It did not matter if the race was the Forest Sring Sprits considered to be the blessings of the nature and had nothing to do with violence, he cannot be acting all trusting and gullible and have to consider many factors before allowing anyone to his main floor.
To put it bluntly, Simon did not trust the [Role] function of the dungeon fully yet. Thus he only wanted those subordinates living on his main floor that he could wholeheartedly trust.
This notion did not occur to him when summoning Irene or when he brought the Forest Spring Spirits here. It was too inconsiderate of him and would have put his life in jeopardy had any of them bore ill intent towards him.