Are the expectations or imaginings of events that a person experiences and which later come to pass, whether positive or negative, merely a coincidence, or a type of fleeting sensation, or is it "the evil eye"?

Absolute unseen is known only by Allah. However, Allah may reveal some of the unseen to some of His righteous servants through inspiration. This is known as al-muḥaddathūn, like Umar ibn al-Khattab, may Allah be pleased with him. There is no religious or rational impediment to this, provided the person is pious and upright. Among other ways of knowing some future matters is firasah, which is the ability to know inner states through outward signs. Only prophets and messengers receive direct revelation from Allah, with the exception of true dreams and true firasah. What the questioner mentioned as examples might be due to the evil eye, which is real and can afflict, by Allah's permission, even from a loved one. It is sunnah for anyone who is impressed by something to supplicate for blessings.