Did Abdullah ibn Salam know the answers to the three questions he asked the Prophet, and can anyone other than prophets know them?

Abdullah ibn Salam came to the Prophet, peace and blessings be upon him, and asked him about things that only a prophet would know. He asked him about resemblance (to parents), about the first thing the people of Paradise will eat, and about the first thing that will gather people (for judgment). The Prophet, peace and blessings be upon him, informed him that Jibreel had told him these things. The Prophet answered him that resemblance depends on which of the two waters (of the man or woman) precedes the other, and the first thing the people of Paradise will eat is the caudate lobe of the whale, and the first thing that will gather people is a fire that will emerge from the East, driving them towards the West. So, Abdullah ibn Salam believed. Abdullah ibn Salam had learned these matters from the previous prophets, and this is what Sheikh al-Islam Ibn Taymiyyah affirmed, explaining that Jewish scholars used to test the Prophet with these questions to ascertain his prophethood.