1: What if the Nationalists were defeated in the Spanish Civil War?
2: What kind of government would they have under the Republicans?
3: Would the Nazis think twice about starting World War Two - like waiting for two years to make sure their army was ready (there are some radical historians that suggest that if Hitler waited to invade Poland for 1-2 years, he might be far more successful)?
4: How would this look from the viewpoint of the spread of Socialism?
1: Under what circumstances? A Civil War just as long at OTL only ending in a republican victory? Does the government receive a tip off about the early nationlist conspiracies and avert the whole thing apart from a few armed clashes in 1936?
2: Depends on the answer to question 1. The longer the war goes on for, the more Stalinist dominated the government becomes/
3: Difficult to say. Maybe a more thorough analysis of lessons learned from the defeat in Spain could lead to major organisational changes
e.g. more of a focus on logistics
4: Now the tricky part. Germany signed the Nazi-Soviet Pact despite sponsoring fighting against socialism in Spain.
If it goes ahead ITTL, which is certainly possible, Spain will see itself as vulnerable and try to defend itself, perhaps by proxy in
the form of "Volunteers" serving with the French Foreign Legion.
I can see Germany crushing Socialist Spain as a warmup to Barbarossa. How this affects their ability to assist the Italians in Greece and North Africa is another matter entirely.
Perhaps they can spin the action in Spain as a means of securing western coast of North Africa.