As for Turkey. I just breifly re-read the mentions of Turkey in Field Marshall Alanbrook's war diary, he was the Chief of the Imperial general staff.
in 1942 He mentions having lunch with a diplomat who tried convincing him that Turkey would never ally with Germany but he says he was not entirely convinced. Later that year the Americans(Marchall) want to close down operation in the Mediterranean after north Africa is cleared and then to land troops in France and to push through Turkey. In January 1943 he mentions further discussion with them that have prevented that(essentially resulting in the plan that went ahead, that being to focus on Italy to deplete German strength).
So early on they(the US) were thinking of invading Turkey or forcing them to side with them.
Later on he travels to North Africa and Egypt with Churchill and makes a brief detour to Turkey to talk about entry in the war with them. He is not impressed by the state of communications or the understating of modern warfare that the Turks have and considers the Turkish to be limited in their usefulness as a fighting force and that it would be difficult to supply them due to the poor communications of Turkey. But he does want to base aircraft there. He adds this post war thought to it
'My 'wild dreams' about Turkey unfortunately remained wild dreams! Von Papen fooled the Turks about fictitious concentrations of German troops in Bulgaria which never existed. This was enough to keep them sitting on the fence, It is a pity as the entry of Turkey would have made a considerable difference, not that the Turkish forces could ever have been trained up and equipped to be of much use, The real value would have ben the use of Turkey for aerodromes and as a jumping off place for future action.'
He also mentions talks with Stalin in '43 in which Stalin doesn't think it worth brining Turkey into the war. He thinks that Stalin probably never wanted Turkey in the war as that would mean US and British troops would be in the dardenelles and would move into the Balkans which he had post war plans for(Stalin is one of the few or maybe only people that Alanbrook has no criticisms of in regards to his strategic sense and indeed he actually thinks highly of it).