MittelAfrika is a stronger possibility if only for a two reasons.
1) Neither France nor Belgium would be in a strong bargaining position.
2) Germany hadn't really lost East Africa.
Sure Britain is in a stronger position, but they get part of what they want by having Germany withdraw from Belgium. Britain likely would try to keep North Africa from trading hands simply for security in the Mediterranean. This could have the strange effect of Italy not having to retrocede Libya to the Ottoman Empire. Germany still could extract a heavy price from Italy in the peace treaty, but the Ottomans aren't going to be able to get Libya back and I doubt Britain would allow Germany to take Libya in the treaty. Germany could still take a stronger position in East Africa by demanding French and Italian possessions on the Horn of Africa, but those demands won't sit well with Britain either since they could be a direct threat to the Suez Canal and ultimately India.
Sounds agreeable here. In the end, if the Germans want to link up their overseas colonies into a contiguous stretch (or, at least, Kamerun and OstAfrika), then that seems like the easiest thing to do. A few border adjustments in Europe (perhaps Luxembourg gets Arlon and some additional territories from Belgium before joining the German Empire, a few small border changes around Alsace-Lorraine).
Germany had effectively lost East Africa at that point, considering that Lettow-Vorbeck's army suffered attrition that couldn't be avoided, and had many fewer reinforcements than British/French colonial troops. There's no way that Germany could effectively retake them. So, yes, I agree with you on them being in the position of strength here.
I'd consider Bermuda and the British Virgin Islands to be stronger possibilities.
Fair enough; I have my reasons against Bermuda, but it does serve a purpose.
We're also assuming the Dutch remain neutral here and the only difference is the US remaining neutral, which leads to a CP victory. The Netherlands aren't really hurting and keeping those possessions in Dutch hands is better for Germany, especially if they're going to try to get the Netherlands in their customs union. Granted, that union is economic, but there's also the prestige element as well. As far as the rest goes, I agree with you these are best case scenarios.
In neutral Netherlands case, you are completely correct. (If the Germans start basing in the Caribbean, things might get messy)
That's exceptionally far-fetched when you consider the British would still be negotiating from a position of strength. Britain is just quitting the war because it has no allies left on the continent. Continuing the war despite that would have not only been bad for the British Colonial Empire, but potentially bad for the United Kingdom at home. Just because Germany wouldn't be able to directly assault Britain doesn't mean Britain wouldn't have its own unrest over staying in the war.
Extremely far-fetched. It might have been better put it as the troll option.
"Germany's negotiating position demands the return of all colonies first and foremost!"
"Oh, sure, old chap! Here you are, all these nice pieces of clay."
"But... You have forgotten German Pacific Protectorates and Samoa!"
"Nonsense, old bean. We simply returned all former German colonies under our possession!"
"But what of German Pacific Possessions. You must have forgotten."
"Bollocks, chap. We really don't have them. Say, you might want to go ask the Americans. They agreed to give us a lien on our debt for a few spots of clay. Bullets and beans don't pay for themselves, ey wat?"
Terrible accents and ridiculous situations aside...
No. Doesn't change anything about Puerto Rico. To make it a state, best to never have Spanish become an official language back in the nineties. English language comprehension has gone down on the island since then (partly aided by flight of the younger population from the island). This PoD shouldn't affect that.
Doubtful. The Virgin Islands (well, not the Spanish ones, at least) did grow a distinct character and have a separate economy. Unless combined early on (pre 1960s), it sounds more likely that they would continue as a separate entity out of inertia. The Virgin Islands also had their economy diverge from Puerto Rico and GDP per capita rose much faster after the 1960s. If combined after that point, there would be the chance of resentment brewing on both sides.
That, and English is already a largely-spoken language in the Virgin Islands. That alone will be a reason for it to be kept separate throughout most of the 20th century.
East Guam.