1st - Please use the www.pcpartpicker.com . Its easy to use and its telling you if there is a problem, are your parts compatible together and etc.
2nd - Yes they are all compatible. The things that could be uncompatible are the CPU and the MOBO, PSU might not have enough W, and etc, but your parts are compatible.
3rd - I wont spend that money on the processor 3450. I would pick up the Intel Core i5-3470. Its cheaper and it delivers to you better performance. And your motherboard supports the 3470 too.
The 12 GB of RAM is because I already have a semi stock ASUS PC which I would be moving over the parts into the new case, as of now my PC has everything listed above except for the case, motherboard, cooler, fan control, and case fans. Thats why I am using some of the parts I'm using.