Yes, all that is pretty well accepted by most biblical scholars now. The rising of Christ was added to Mark well after the first part was written.
Another interesting thing I have learned is that the 2nd chapter of Genesis was actually written before the 1st chapter. Scholars also believe that the Psalms are the oldest writings and Yahweh is not creating anything in them. In fact, he is shown to sit down with a council of gods somewhat like was formed in the Cannonite society. The young Yahweh in the beginning was not a cosmic creator but only a creator of man. Also, archeology now shows that there was likely never an Exodus and that the Israelite religion very likely started within the Cannanites. El was their major god and Yahweh himself says he started as El. In Exodus 6 Yahweh is talking to Moses and he says "I am Yahweh. I appeared to Abraham, to Isaac, and to Jacob as El shaddai, but by my name Yahweh I did not make myself known to them." Even Yahweh himself says that he started life with the name El.
Historically, when two religions joined gods merged and became the same. If you are trying to meld to religions you are trying to convince two groups of people. One that worships Yahweh and another that worships a god called El and that they are actually the same god so that people have no trouble with merging the two. It's interesting that El is even in the word Israel.