All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu ʻalayhi wa sallam, is His Slave and Messenger.
Dear questioner, we apologize for not reading the Fatwa referred to in the question.
As for your question, you should know that guessing based on scientific facts, previous experiences and experiments, or observations of the real world, does not fall into the category of the prohibited guessing at the unseen and there is no problem with that.
Ibn ʻUmar narrated that the Prophet, sallallaahu ʻalayhi wa sallam, said: “Amongst the trees, there is a tree, the leaves of which do not fall and is like a Muslim. Tell me the name of that tree.” Everybody started thinking about the trees of the desert areas. And I thought of the date-palm tree but felt shy to answer the others then asked, “What is that tree, O Messenger of Allah?" He, sallallaahu ʻalayhi wa sallam, replied: “It is the date-palm tree." Ibn ʻUmar added, "I told my father what had come to my mind and on that he, sallallaahu ʻalayhi wa sallam, said, 'Had you said it I would have preferred it to such and such a thing that I might possess.’”[Al-Bukhaari and Muslim]
ʻUmar, sallallaahu ʻalayhi wa sallam, guessed that the Prophet, sallallaahu ʻalayhi wa sallam, was talking about the palm-tree and there is nothing wrong with that. Al-Bukhari cited this Hadeeth in a chapter entitled “Chapter: The Imam questioning his companions in order to test their knowledge.”
Allah knows best.