1) What happens if a word sounds very similar to a doer or receiver pattern but it doesn’t match exactly, i.e. عالَمين from Sūrat al-Fātiḥah?
The ḥarakāt are essential to the structure of a pattern, so even if one ḥarakāh is off it cannot fit into these categories. The changes in ḥarakāt usually indicate other patterns.