To be more precise, I didn't meant exactly an all out conflict, but basically that due to the unavoidably fractured nature of Egypt that a Latin conquest will result in (), the control of Egypt riches will be a struggle and a game of influence, and at this game, the Byzantines are way, way stronger (and have longer, centuries long experience as well) than Jerusalem and the Italian maritime republics, so if the Italo-Latins can't get their way diplomatically, the military way is the only way left (and here, I thinking of proxy conflicts between respective client states). I'm well aware that Egypt's conquest is a foregone conclusion, I'm just thinking that whatever political settlement there is after the conquest, I'm pretty sure of two things, first it won't be annexed to Jerusalem and second, it will be anything but united and centralized and end up as a bunch of client states spanning the Nile valley from Nubia down to the delta, not to mention the oases in the western desert (Siwa, Fayum...) under the influence of one or another Italian maritime republic or Rhomaion with Latin sovereignty nominal at best. Once you remove Damascus (and Homs incidentally since there is no reason to keep it independent without Damascus to bother with), and especially Egypt from the equation, Jerusalem will no longer have a vital need of Rhomaion support as there would be only left the Syrian-Mesopotamian border left to worry about, one that Jerusalem could very well think and be actually capable to defend on its own.
Your considerations are precise, my friend. We'll very much likely see these sorts of patterns, including the fate of Homs and Damascus, and the relations towards the ERE. I liked the idea of seeing proxy conflicts between spheres of influence, and, overall we might have some sort of "Great Game" in the eastern Mediterranean. However, I do tend to suppose that, when the day comes for a war between the Latins and the Romans, Constantinople will be very wary of "isolating" itself from western Christendom, so to speak; that is, they will go to great lengths to legitimize their own position, so as to avoid further debacles with the Papacy, the HRE, the Italian republics and other Latin monarchies, while the Crusaders, on the other hand, even if counting with Papal support, won't be so quick to alienate Constantinople. Your prediction about a possible "Cold War" between them, to dispute the fate of the Near East and (likely) North Africa is very sensible.
Much case has been made about Italian settlers, but what of German and French ones? Are they so few that they aren't mentionned next to the Italians?
I focused on the Italians just to compare with OTL, in which we saw the French playing a considerably larger role in the Outremer (with all the dynastic houses being installed by French nobles, and such, like the Angevines and the Lusignans), while Italy, in spite of its economic and populational relevance, had a comparatively minor impact (until the Fourth Crusade, at least, which saw a large role played by Venice and Montferrat). The previous entry focused on Italians just to show this divergence in comparison to OTL, but this obviously doesn't means that we won't be seeing peoples from other regions of Europe. The whole Francophone region (France proper, Brittany, Flanders and Burgundy) are a given, and we'll usually see French nobles and monarchs on Crusade. The Germans too, and there has been a lot of mentions about the regions of southern Germany (Swabia and Bavaria) and especially the Rhineland, which was experiencing a rapid process of urbanization in the period.
Any chance that some of those Bosnian slaves end up in Caesarea? :3 Interestingly enough it was 19th century Bosnian immigrants escaping religious violence in the Balkans who built modern-day Caesarea and have many descendants amongst the Palestinian population. On the other end, how are the local Christians and Muslims reacting to the influx of European migrants?
That's very interesting, I didn't know about the Bosnians. This curiosity will much likely warrant mentions, you can be sure about that
Local Christians and Muslims don't really have much of a say in the matter. Some friction and perhaps even revolts are bound to happen due to the conflicting interests, but, as a general rule of thumb, the established communities won't be universally affected by these influxes, as they will happen during the course of many decades. Also, the Latin immigrants will tend to focus geographically in coastal Palestine, in central Lebanon and Syria, so we'll see that these local Levantine communities won't necessarily be displaced by the new arrivals. Palestine, in particular, is a difficult region due to its mountainous and hilly geography, but, even so, it was relatively underpopulated before the arrival of the Crusaders due to its peripheral character as a province during the rule of the Caliphates, while Lebanon and Syria have considerably larger populations.