This if I may so note is a bit shallow view of Venizelos. To very roughly quote Travlos from
Salvation and Catastrophe the first joint study by Greek and Turkish scholars on the Asia Minor war, Venizelos political coalition was an intersection of middle class in the free kingdom, diaspora Greeks and Ottoman Greeks. As such it had a vested interest in the survival and well being of Ottoman Greeks not least because the diaspora Greeks and free kingdom middle classes made a fair bit of their profits from trade and investment in the Ottoman empire run by Ottoman Greeks (and vice versa).
So the obvious question here is, how is the TTL Ottoman empire dealing with its Greek populations? Still second class citizens but otherwise mostly left alone to their own devices (What Greeks were mostly experiencing under Abdul Hamid)? Fully equal? In danger of getting ethnic cleansed and massacred (say hi to CUP and the three pashas)? What Venizelos in particular and Greece in general would be doing very much depends on this. The so called "Eastern Federation", alliance with the Ottomans and even a dual Greek-Turkish monarchy were all seriously considered at the time. If the Ottoman Greeks are getting full equality for real the policy of the free kingdom will be also gravitating towards accomodation with Constantinople. And this very much includes Venizelos.
Minor note, Venizelos while born in Crete had Greek citizenship. That Crete is still Ottoman does not mean he canot be a politician in Greece.
Yes we know the TL is a dystopia from the moment the Confederates won.
"Muslim Bulgarian" in this era, sure you have largish Muslim populations that speak Bulgarian dialects. This does not mean they also usually identify as Bulgarian. Just like Ireland religion tends to trounce language in the Ottoman Balkans when it comes to self identification.
Thessaly, Epirus, Crete and of course the Aegean islands and Cyprus.
TTL he is lucky, short of in that his pro-German tendencies, assuming of course he married his Prussian bride and did not end up studying in Paris, are not antithetical to his country's interests and geography.
Closer relations with Germany or for that matter Italy are not in opposition to close relations with Britain. Quite the opposite arguably, with France firmly pro-Ottoman for the past two generations. If anything TTL for Venizelos in Athens the news of the Anglo-German deals would be excellent ones, Greece's two main potential allies are coming together,what is not to like? Arguably Greece was bringing in German military missions in place of the French ones to organize its army, and the Germans get the lion's share of arms orders. The navy is still getting either a British mission of if the British for some reason were not forthcoming with one an American one (OTL they did try yo get a US training mission around 1904 or so, don't recall exact date)
Are they? OTL particularly after 1870 they were not all that warm. Greece wasn't neutral despite strong Russian pressure in 1878 by accident. Panslavism was being thought of as the big and primary danger which meant Russia and her support for Bulgaria.