I can't provide many book references, but generally I'd advise you read Emile Nakhleh's blog (and probably books too!), he's an American-Palestinian who worked for the CIA for years as a Middle East analyst, and unfortunately it seems like his advice always gets ignored regardless of how insightful it is.
Does Turkey really support ISIS
Russia thinks so. America has denied this evidence, but it's important to point out that they've been going soft on Turkey lately; probably because it allows US forces and allies to base there to strike ISIL targets. Otherwise there's good arguments for this being true.
What has Russia really been doing in Syria?
NATO thinks it's nothing to do with ISIL, and instead is based in geopolitics. Which chimes with a US claim that over 90% of Russian airstrikes have not hit ISIL targets. Historically Syria and Russia were BFFs during Soviet times, and since then the two nations have been partners in Russia's arms trade and the fight against Islamists who threaten both nations security. There's also the curious case of the blood ties between the two peoples, as during the cold war Russian women who otherwise had no access to the outside world married nice Syrian men to be able to travel the world.
Who's the "bad guy" between Israel and Palestine?
Pfft! Next question.
Did killing/ousting Saddam Hussein solve anything? Was he really that
bad of a head of state?
You've got to understand just how important the Ba'ath party was to the functioning of Iraqi society before Saddam was ousted, and thus how dire the decision to disband it was. Saddam's regime improved the country economically, but there's a reason it's referred to as "the republic of fear". Killing Saddam meant that his loyalists had nowhere left to go, especially since they now feared for their lives due to Shia reprisals for injustices suffered during Saddam's time.
What's the whole deal with Wahhabism? Is Saudi Arabia really the prime
supporter/funder/exporter of terrorism?
Yes. See Emile's blog. It's not so much that Saudi gave funding to ISIL, but that Saudi education and religious charity legitimised and exported the intellectual framework for Al-Qaeda, ISIL, etc. However, these extremists and Saudi's royals are mortal enemies, both view the other rightly as an existential threat, and this is a reflection of Saudi internal politics.
You see ever since Saudi Arabia came to be there's been a rivalry between the religious establishment and the royals, and there are many cases where there has been a religious backlash to attempts by the King to modernise the country. The Grand Mosque seizure is a good case study. Saudi kings have used religious fanatics to create and legitimise their kingdom, this dates back to Abd al-Aziz using the Ikhwan to create his Saudi kingdom before machinegunning them in the desert.
Did US interventionism in the ME really cause the rise of terrorist
groups such as ISIS?
Yes. Whatever way you look at it, American incompetence was instrumental in building the kindling for the coming fire. From the aforestated de-Baathification driving unmemployed Iraqi soldiers into an insurgency, to inadvertently providing the networking opportunities in camp Bucca for ISIL to come into existence. But it wasn't just America, the last link also discussed how an unholy alliance between Iraqi Baathists and jihadis was facilitated by Syria. Without Syrian Baathist support ISIL couldn't have got the men and material it needed to make gains in Iraq. Given how things have turned out for Syria, it was an ironic twist of fate.
I hope those links are helpful!