As as Christian myself, I can honestly say that you are reading way too much into it. Within the Assasin's Creed lore, Jesus was killed by the Order of the Ancients/ Templars, the overarching bad guys of the series, not by the Assassins. Christians are never really portrayed as the villains in the series, the villains just disguise themselves as Christians sometimes, for instance the Borgia Pope in the Ezio games; they're not actual Christians, they just pretend to be. I will say that AC is not exactly the most Christian friendly series, but there are far, far worse series for Christians to play.

The whole point of having a Viking game is to play as a Viking, would be a pointless game that few would want to play if you played as the British repelling the Viking raids. Vikings are so popular that it was inevitable that we would get a Viking Assassin's Creed at some point. And they're not going to have you play as the villains, murdering and pillaging, they tried an AC where you play as a villain once, AC Rogue, and it wasn't very popular. So the only way to do it is to portray the Vikings as the good guys. The Order of the Ancients/Templars control the narrative of history within the franchise, using their power and connections, that is why we as modern humans remember the Vikings as murderous pillagers and the English king as a hero who repelled them, one of only 2 English kings to earn the epithet "the Great", the game shows us the "truth" is the opposite. 

The trailer already gives you some idea of that. We hear Alfred saying that vikings murder and kill blindly during a scene of some vikings purposefully sparing a woman and child that cross their path. We hear Alfred talking about how bad they are, but see a scene of vikings playing with their children. 

Be sure to read the 2nd paragraph I edited in above.

The AC series has never been designed to be historically accurate in terms of the storyline. I mean the pirates were the good guys in AC4, lol. They go to painstaking lengths to achieve historical accuracy in some ways, for instance creating the worlds based on historical maps and dressing the characters in period accurate clothing and armor, but in terms of story AC has always played it fast and loose with historical accuracy. Afterall, they have to work in a plot about 2 fictional orders, the Assassin Brotherhood and The Order of the Ancients/Templars, working against each other across thousands of years of history. A plot where all world religions are based on the worship of either members of the First Civilization (the first sentient race to inhabit earth before humans) or humans who used First Civilization artifacts to perform seemingly miraculous feats. 

So Ubisoft are basically going to go into this historically incorrect then and make up their own version of vikings lol.

Maybe they will have the monks raping the viking women instead. 

So Ubisoft are basically going to go into this historically incorrect then and make up their own version of vikings lol.

Maybe they will have the monks raping the viking women instead.