The Qur’an is clear and fully-detailed?

While speaking to Qur’an-only Muslims, they often say that the Qur’an is clear and fully-detailed and, since they can’t draw upon hadith, it is even more important that this be true. In a recent conversation, I listed a few reasons why I don’t think it’s always fully-detailed or clear:

• The Qur’an says to pray, fast, do hajj etc. but gives precious few instructions as to how this should be done.
• Dhu al-Qarnayn is mentioned, but the text doesn’t say who he is.
• Likewise, the Qur’an references lots of figures from Israelite history and assumes the reader knows about these people and events. This becomes far more problematic if one thinks that that earlier revelation has been corrupted.
• Surah 66 gives precious few details about the dispute to which it refers. All you can really tell is that Muhammad denied himself something to try and please his wives and Allah is displeased.
• In 17:1, who travelled and to where did they go?
• After reading the account of Isa’s crucifixion, I’ve still got no idea what actually happened. Was Judas swapped out? Someone else? Why didn’t Allah just visibly save Isa, rather than convincing everyone that the crucifixion happened and thereby beginning Christianity? It describes Jesus as “Messiah” but doesn’t explain what that means or why he alone has a virginal conception.
• The Qur’an says that Isa/Jesus is the “Messiah”, but what does it mean to be the Messiah?
• What does Alif, Lam, Ra mean?
• The Qur’an repeatedly singles out one particular brother of Joseph (“Yusuf”). Who is it? What was the name of his bother?
• With how many women did Jacob (“Yaqub”) have children?
• Name the twelve tribes of Israel mentioned in 7:160
• Where was Jesus born?
• Where and when did Jesus conduct His ministry?
• Can you name Jesus’ disciples?
• Are Israel and Jacob the same person?
• What Scripture did Moses bring?
• Can Muslims marry Christians? Some passages seem to suggest “yes”, but other passages say Muslims can’t marry polytheists, and that is the charge against Christians which would mean the answer would be “no”.

Many more could be added… One ultimately has to assume that none of this is important, which is just another way of saying that not everything is clear or fully-explained.