It appears as if the cantilevered deck is creating a bending moment about lintel on the top of the window, thus resulting in a lateral cracking above and below the window.
I would recommend something similar to "Quikrete" or "Sika" products.
Lap length (aka. splice length), should be determined based on the size of your vertical reinforcement. These lengths can be found in the ACI concrete design manual as "development lengths". It is very important to ensure...
The wall can be poured in separate pours provided that you allow for for adequate lap length of your vertical reinforcement. Also, a bonding agent should be used on non-monolithic pours to ensure that the concrete is adequately sealed at the construction joint(s).
