I'm fairly certain any claim that Japan would accept the Potsdam Declaration before the nuclear bombings is just outright wrong: Japan was still operating under the assumption that the USSR might be willing to negotiate on Japan's behalf before the USSR's own invasion, so Japan still believed it might be able to hold on to something at that point.

Generally speaking, each lord contributing soldiers had to meet a certain standard, and the soldiers in question usually had a high enough status to equip themselves. It's likely there was some form of subsidy by the lord, but that would be case-by-case, like a lord acting as a creditor for a bulk order if payment was in goods instead of coin.

The profit from the American colonies came mostly from the food that was exported to the more lucrative Caribbean islands, and the lumber industry, which was needed for the ships.

The English tax system itself had trouble taxing America, because Americans didn't have enough gold or silver to make that easy, and customs officials in America were practically on their own, which made them easy to threaten.

The only practical method of tax was thus forcing all goods to come in and out of Britian, which probably caused more problems than it solved.

The Americans were rooted in British culture, but had very much become their own nation, if not their own state, in the roughly 150 years of the first permanent settlements:

1. The Americans had their own view of who was gentry (or who could vote, basically,) and this was massively more broad than what the British would ever accept.

2. The Americans saw fighting in war as a patriotic demonstration, which was not a sentiment shared by British officers.

3. The fighting with the natives was far more personal to the Americans than anyone from Britian.

4. The British saw the American colonies as insignificant compared money sinks compared to the deeply lucrative colonies elsewhere.

5.1 Because gold and silver were so rare, bank notes backed by land and debts were practically the backbone of the American economy. This became a major issue when the British banks allowed borrowers to overleverage, as they passed laws to reduce the quantity of American notes, and bar their use as payment, while also reducing speice sent to America.

5.2 Needless to say, combining deflation with the mercantilist policies led to disaster dominos, since Spanish currency was even more common than British money before this, so increasing the imbalance further would almost certainly benefit those who were already breaking British laws.

6. Americans also had a tradition of getting what they wanted by rioting at this point, so the British decision to give their governors the soldiers they would actually need to prevent this came far too late.

So basically, there were a LOT of cultural differences by the time of the revolution.

Adding to this, animals were (and are) massive disease vectors: if large numbers weren't present, that alone cuts down the risks dramatically.

Just as an example, one of the worst outbreaks in history came from the horses of nomads around China.

It certainly happened: Robert of St. Albans being one of the more famous examples, when he joined Saladin. Leon Cazelier also famously betrayed a castle, and later converted.

The Templars even ended up with a reputation for converting to Islam, but it was mostly undeserved, since pretty much everyone had their share of traitors.

It was never a common occurrence, of course.

As a non-religious example, Columbus: while someone else would have done the same eventually, it was his accidental discovery of gold in the "New World" that dramatically changed the nature of Spain's interest. In general, a slower exploration of America would be likely, shifting the fortunes of Spain at a minimum, which would in turn massively shift events in the early modern world.

Many of the natives tried to build exactly the kind of alliance you're talking about, but practically, such a cause was always doomed: steel tools and gunpowder were simply too powerful as force multipliers to ignore, and weaker tribes saw no practical diffrence in being evicted from their land by a rival tribe instead of the Europeans.

And once a tribe takes to using gunpowder weapons and steel, it's stuck: killing all the Europeans is the same as signing one's own death warrant, because the skills needed to be independent are lost. Even if they accept that, all that changes is that the French take over instead.

Doubtful: the effective air superiority of the Germans destroyed practically all of the french heavy artillery, and made moving reinforcements by train difficult. The French army also didn't have the training and AT guns it desperately needed due to earlier cost cutting (only 20% of the French tanks even had radios,) and the end result was that the French army was too demoralized to attack even when the German tanks were too far ahead of their infantry, which was the only time France might have been able to reverse the situation, at least for a time.

Besides the obvious, I assume?

The Galleon would generally have had around 38 guns as a main battery, with more, generally smaller guns, if it was being used as a warship. The additional weight needed for war could cause problems, though, like the extra weight causing ships to partially fill the bottom decks with water; the end result was clunky, if not outright dangerous. Unsurprisingly, they also tended to be quite slow given their bulk, which caused serious problems for the Spanish Armada during its infamous attack on England.

Dedicated warships would come to be double-planked in the 17th Century, making the hull more resistant to guns, and the rigging was also improved. If we're going even further to the 18th, and also going all out by comparing Galleons like the Triumph (roughly the same kind of class used by Francis Drake,) with the Océan class (probably the most advanced class of its century,) we get:

1. A tonnage of 1000 for the galleon against 2750 of the warship.
2. 124–136 heavier guns against a roughly 1/3 of lighter for the galleon.
3. The 10 knots of the warship against the 8 knots of the non-war prepared Golden Hind.
4. Such a difference in sailing characteristics that weather which would sink a war galleon could be at least survived by the Océan class.

Suffice to say, a fight between the two would be quite the massacre.

Rounded seem more common on dedicated warships (at least for Spain,) being able to place more cannons at the front, but the type was never really satisfactory, so there were many attempts to adjust the design to something that would work.

I don't really understand what you mean:

1.Lee was also going to be put on trial in the immediate aftermath of the war, so I'm not sure how Lee was supposed to defend him, exactly.

2. Lee wrote that he was ill in 1868, and Lee died in 1870, which was the point in time where most of the criticism of Longstreet came to be.

That's going to depend massively on the future political landscape: 100 years ago, France would have told you that German history would be much more important to study for the future of Europe than US history, because they would have no way of knowing how greatly circumstances would change during the Cold War.

The only real deception would have been about the sheer distance to travel, and even that was probably more out of general ignorance than bad faith.

The crusaders knew full well they had nothing to inherit, and most would have been lucky to have enough equipment to qualify as heavy cavalry. Becoming a crusader thus encouraged families to pay for better equipment, and helped the crusaders to receive far more support from strangers who would otherwise have no reason to aid them. Just look at the difference in support Ukriane has gotten compared to something like Yemen, and you can start to appreciate how big a diffrence ideology actually makes.

Not to be too cynical, of course: few would likely leave everything they knew behind if faith wasn't a genuine motivator, and all but the most ambitious could probably have found easier employment along the way if they looked hard enough. That so many endured great hardships for so long is difficult to attribute to mere pragmatism.

Metallurgy is the big one: it isn't like everyone was too dumb to understand why steam is great to use, but if the pipes continually burst, you're kinda just wasting time.